diff --git a/application/helpers/SurveyRuntimeHelper.php b/application/helpers/SurveyRuntimeHelper.php
index b19bd6490e4..4ff46fa0e57 100644
--- a/application/helpers/SurveyRuntimeHelper.php
+++ b/application/helpers/SurveyRuntimeHelper.php
@@ -23,6 +23,7 @@ class SurveyRuntimeHelper {
     */
     function run($surveyid,$args) {
         extract($args);
+        $LEMsessid = 'survey_' . $surveyid;
 
         // $LEMdebugLevel - customizable debugging for Lime Expression Manager
         $LEMdebugLevel = 0;   // LEM_DEBUG_TIMING;    // (LEM_DEBUG_TIMING + LEM_DEBUG_VALIDATION_SUMMARY + LEM_DEBUG_VALIDATION_DETAIL);
@@ -52,10 +53,10 @@ function run($surveyid,$args) {
         'hyperlinkSyntaxHighlighting' => (($LEMdebugLevel & LEM_DEBUG_VALIDATION_SUMMARY) == LEM_DEBUG_VALIDATION_SUMMARY), // TODO set this to true if in admin mode but not if running a survey
         'ipaddr' => ($thissurvey['ipaddr'] == 'Y'),
         'radix'=>$radix,
-        'refurl' => (($thissurvey['refurl'] == "Y") ? $_SESSION['survey_'.$surveyid]['refurl'] : NULL),
+        'refurl' => (($thissurvey['refurl'] == "Y") ? $_SESSION[$LEMsessid]['refurl'] : NULL),
         'savetimings' => ($thissurvey['savetimings'] == "Y"),
         'surveyls_dateformat' => (isset($thissurvey['surveyls_dateformat']) ? $thissurvey['surveyls_dateformat'] : 1),
-        'startlanguage' => (isset($_SESSION['survey_'.$surveyid]['s_lang']) ? $_SESSION['survey_'.$surveyid]['s_lang'] : 'en'),
+        'startlanguage' => (isset($_SESSION[$LEMsessid]['s_lang']) ? $_SESSION[$LEMsessid]['s_lang'] : 'en'),
         'target' => (isset($uploaddir) ? "{$uploaddir}/surveys/{$thissurvey['sid']}/files/" : "/temp/{$thissurvey['sid']}/files"),
         'tempdir' => (isset($tempdir) ? $tempdir : '/temp/'),
         'timeadjust' => (isset($timeadjust) ? $timeadjust : 0),
@@ -79,18 +80,18 @@ function run($surveyid,$args) {
 
         if ($previewgrp || $previewquestion)
         {
-            $_SESSION['survey_'.$surveyid]['prevstep'] = 1;
-            $_SESSION['survey_'.$surveyid]['maxstep'] = 0;
+            $_SESSION[$LEMsessid]['prevstep'] = 1;
+            $_SESSION[$LEMsessid]['maxstep'] = 0;
         }
         else
         {
 
             //RUN THIS IF THIS IS THE FIRST TIME , OR THE FIRST PAGE ########################################
-            if (!isset($_SESSION['survey_'.$surveyid]['step']))  //  || !$_SESSION['step']) - don't do this for step0, else rebuild the session
+            if (!isset($_SESSION[$LEMsessid]['step']))  //  || !$_SESSION[$LEMsessid]['step']) - don't do this for step0, else rebuild the session
             {
                 $totalquestions = buildsurveysession($surveyid);
                 LimeExpressionManager::StartSurvey($thissurvey['sid'], $surveyMode, $surveyOptions, false, $LEMdebugLevel);
-                $_SESSION['survey_'.$surveyid]['step'] = 0;
+                $_SESSION[$LEMsessid]['step'] = 0;
                 if ($surveyMode == 'survey')
                 {
                     $move = "movenext"; // to force a call to NavigateForwards()
@@ -98,21 +99,21 @@ function run($surveyid,$args) {
                 else if (isset($thissurvey['showwelcome']) && $thissurvey['showwelcome'] == 'N')
                     {
                         //If explicitply set, hide the welcome screen
-                        $_SESSION['survey_'.$surveyid]['step'] = 0;
+                        $_SESSION[$LEMsessid]['step'] = 0;
                         $move = "movenext";
                     }
             }
 
-            if (!isset($_SESSION['survey_'.$surveyid]['totalsteps']))
+            if (!isset($_SESSION[$LEMsessid]['totalsteps']))
             {
-                $_SESSION['survey_'.$surveyid]['totalsteps'] = 0;
+                $_SESSION[$LEMsessid]['totalsteps'] = 0;
             }
-            if (!isset($_SESSION['survey_'.$surveyid]['maxstep']))
+            if (!isset($_SESSION[$LEMsessid]['maxstep']))
             {
-                $_SESSION['survey_'.$surveyid]['maxstep'] = 0;
+                $_SESSION[$LEMsessid]['maxstep'] = 0;
             }
 
-            if (isset($_SESSION['LEMpostKey']) && isset($_POST['LEMpostKey']) && $_POST['LEMpostKey'] != $_SESSION['LEMpostKey'])
+            if (isset($_SESSION[$LEMsessid]['LEMpostKey']) && isset($_POST['LEMpostKey']) && $_POST['LEMpostKey'] != $_SESSION[$LEMsessid]['LEMpostKey'])
             {
                 // then trying to resubmit (e.g. Next, Previous, Submit) from a cached copy of the page
                 // Does not try to save anything from the page to the database
@@ -138,19 +139,19 @@ function run($surveyid,$args) {
 
             if (!(isset($_POST['saveall']) || isset($_POST['saveprompt']) || isset($_POST['loadall']) || isset($_GET['sid']) || $LEMskipReprocessing || (isset($move) && (preg_match('/^changelang_/',$move)))))
             {
-                $_SESSION['survey_'.$surveyid]['prevstep'] = $_SESSION['survey_'.$surveyid]['step'];
+                $_SESSION[$LEMsessid]['prevstep'] = $_SESSION[$LEMsessid]['step'];
             }
-            if (!isset($_SESSION['prevstep']))
+            if (!isset($_SESSION[$LEMsessid]['prevstep']))
             {
-                $_SESSION['survey_'.$surveyid]['prevstep']=-1;   // this only happens on re-load
+                $_SESSION[$LEMsessid]['prevstep']=-1;   // this only happens on re-load
             }
 
-            if (isset($_SESSION['LEMtokenResume']))
+            if (isset($_SESSION[$LEMsessid]['LEMtokenResume']))
             {
                 LimeExpressionManager::StartSurvey($thissurvey['sid'], $surveyMode, $surveyOptions, false,$LEMdebugLevel);
-                $moveResult = LimeExpressionManager::JumpTo($_SESSION['survey_'.$surveyid]['step']+1,false,false);   // if late in the survey, will re-validate contents, which may be overkill
-                unset($_SESSION['LEMtokenResume']);
-                unset($_SESSION['LEMreload']);
+                $moveResult = LimeExpressionManager::JumpTo($_SESSION[$LEMsessid]['step']+1,false,false);   // if late in the survey, will re-validate contents, which may be overkill
+                unset($_SESSION[$LEMsessid]['LEMtokenResume']);
+                unset($_SESSION[$LEMsessid]['LEMreload']);
             }
             else if (!$LEMskipReprocessing)
                 {
@@ -160,17 +161,17 @@ function run($surveyid,$args) {
                         $moveResult = LimeExpressionManager::NavigateBackwards();
                         if ($moveResult['at_start'])
                         {
-                            $_SESSION['survey_'.$surveyid]['step'] = 0;
+                            $_SESSION[$LEMsessid]['step'] = 0;
                             unset($moveResult); // so display welcome page again
                         }
                 }
                 if (isset($move) && $move == "movenext")
                 {
-                    if (isset($_SESSION['survey_'.$surveyid]['LEMreload']))
+                    if (isset($_SESSION[$LEMsessid]['LEMreload']))
                     {
                         LimeExpressionManager::StartSurvey($thissurvey['sid'], $surveyMode, $surveyOptions, false, $LEMdebugLevel);
-                        $moveResult = LimeExpressionManager::JumpTo($_SESSION['survey_'.$surveyid]['step'], false, false);   // if late in the survey, will re-validate contents, which may be overkill
-                        unset($_SESSION['survey_'.$surveyid]['LEMreload']);
+                        $moveResult = LimeExpressionManager::JumpTo($_SESSION[$LEMsessid]['step'], false, false);   // if late in the survey, will re-validate contents, which may be overkill
+                        unset($_SESSION[$LEMsessid]['LEMreload']);
                     }
                     else
                     {
@@ -187,23 +188,23 @@ function run($surveyid,$args) {
                     {
                         // may be submitting from the navigation bar, in which case need to process all intervening questions
                         // in order to update equations and ensure there are no intervening relevant mandatory or relevant invalid questions
-                        $moveResult = LimeExpressionManager::JumpTo($_SESSION['survey_'.$surveyid]['totalsteps'] + 1, false);
+                        $moveResult = LimeExpressionManager::JumpTo($_SESSION[$LEMsessid]['totalsteps'] + 1, false);
                     }
                 }
                 if (isset($move) && (preg_match('/^changelang_/', $move)))
                 {
                     // jump to current step using new language, processing POST values
-                    $moveResult = LimeExpressionManager::JumpTo($_SESSION['survey_'.$surveyid]['step'], false, true, false, true);  // do process the POST data
+                    $moveResult = LimeExpressionManager::JumpTo($_SESSION[$LEMsessid]['step'], false, true, false, true);  // do process the POST data
                 }
                 if (isset($move) && isNumericInt($move) && $thissurvey['allowjumps'] == 'Y')
                 {
                     $move = (int) $move;
-                    if ($move > 0 && (($move <= $_SESSION['survey_'.$surveyid]['step']) || (isset($_SESSION['survey_'.$surveyid]['maxstep']) && $move <= $_SESSION['survey_'.$surveyid]['maxstep'])))
+                    if ($move > 0 && (($move <= $_SESSION[$LEMsessid]['step']) || (isset($_SESSION[$LEMsessid]['maxstep']) && $move <= $_SESSION[$LEMsessid]['maxstep'])))
                     {
                         $moveResult = LimeExpressionManager::JumpTo($move, false);
                     }
                 }
-                if (!isset($moveResult) && !($surveyMode != 'survey' && $_SESSION['survey_'.$surveyid]['step'] == 0))
+                if (!isset($moveResult) && !($surveyMode != 'survey' && $_SESSION[$LEMsessid]['step'] == 0))
                 {
                     // Just in case not set via any other means, but don't do this if it is the welcome page
                     $moveResult = LimeExpressionManager::GetLastMoveResult(true);
@@ -219,7 +220,7 @@ function run($surveyid,$args) {
                 }
                 else
                 {
-                    $_SESSION['survey_'.$surveyid]['step'] = $moveResult['seq'] + 1;  // step is index base 1
+                    $_SESSION[$LEMsessid]['step'] = $moveResult['seq'] + 1;  // step is index base 1
                     $stepInfo = LimeExpressionManager::GetStepIndexInfo($moveResult['seq']);
                 }
                 if ($move == "movesubmit" && $moveResult['finished'] == false)
@@ -234,9 +235,9 @@ function run($surveyid,$args) {
             // Previously we used to keep the session and redirect the user to the
             // submit page.
 
-            if ($surveyMode != 'survey' && $_SESSION['survey_'.$surveyid]['step'] == 0)
+            if ($surveyMode != 'survey' && $_SESSION[$LEMsessid]['step'] == 0)
             {
-                $_SESSION['test']=time();
+                $_SESSION[$LEMsessid]['test']=time();
                 display_first_page();
                 exit;
             }
@@ -244,7 +245,7 @@ function run($surveyid,$args) {
             //CHECK IF ALL MANDATORY QUESTIONS HAVE BEEN ANSWERED ############################################
             //First, see if we are moving backwards or doing a Save so far, and its OK not to check:
             if (
-            (isset($move) && ($move == "moveprev" || (is_int($move) && $_SESSION['survey_'.$surveyid]['prevstep'] == $_SESSION['survey_'.$surveyid]['maxstep']) || $_SESSION['survey_'.$surveyid]['prevstep'] == $_SESSION['survey_'.$surveyid]['step'])) ||
+            (isset($move) && ($move == "moveprev" || (is_int($move) && $_SESSION[$LEMsessid]['prevstep'] == $_SESSION[$LEMsessid]['maxstep']) || $_SESSION[$LEMsessid]['prevstep'] == $_SESSION[$LEMsessid]['step'])) ||
             (isset($_POST['saveall']) && $_POST['saveall'] == $clang->gT("Save your responses so far")))
             {
                 if (Yii::app()->getConfig('allowmandbackwards') == 1)
@@ -268,7 +269,7 @@ function run($surveyid,$args) {
             if ($thissurvey['active'] == "Y" && isset($_POST['saveall']))
             {
                 // must do this here to process the POSTed values
-                $moveResult = LimeExpressionManager::JumpTo($_SESSION['survey_'.$surveyid]['step'], false);   // by jumping to current step, saves data so far
+                $moveResult = LimeExpressionManager::JumpTo($_SESSION[$LEMsessid]['step'], false);   // by jumping to current step, saves data so far
 
                 $cSave->showsaveform(); // generates a form and exits, awaiting input
             }
@@ -325,7 +326,7 @@ function run($surveyid,$args) {
             //SEE IF THIS GROUP SHOULD DISPLAY
             $show_empty_group = false;
 
-            if ($_SESSION['survey_'.$surveyid]['step'] == 0)
+            if ($_SESSION[$LEMsessid]['step'] == 0)
                 $show_empty_group = true;
 
             $redata = compact(array_keys(get_defined_vars()));
@@ -336,9 +337,9 @@ function run($surveyid,$args) {
                 //                setcookie("limesurvey_timers", "", time() - 3600); // remove the timers cookies   //@todo fix - sometimes results in headers already sent error
                 if ($thissurvey['refurl'] == "Y")
                 {
-                    if (!in_array("refurl", $_SESSION['survey_'.$surveyid]['insertarray'])) //Only add this if it doesn't already exist
+                    if (!in_array("refurl", $_SESSION[$LEMsessid]['insertarray'])) //Only add this if it doesn't already exist
                     {
-                        $_SESSION['survey_'.$surveyid]['insertarray'][] = "refurl";
+                        $_SESSION[$LEMsessid]['insertarray'][] = "refurl";
                     }
                 }
 
@@ -368,9 +369,9 @@ function run($surveyid,$args) {
                     // fetch all filenames from $_SESSIONS['files'] and delete them all
                     // from the /upload/tmp/ directory
                     /* echo "<pre>";print_r($_SESSION);echo "</pre>";
-                    for($i = 1; isset($_SESSION['files'][$i]); $i++)
+                    for($i = 1; isset($_SESSION[$LEMsessid]['files'][$i]); $i++)
                     {
-                    unlink('upload/tmp/'.$_SESSION['files'][$i]['filename']);
+                    unlink('upload/tmp/'.$_SESSION[$LEMsessid]['files'][$i]['filename']);
                     }
                     */
                     $completed = $thissurvey['surveyls_endtext'];
@@ -463,7 +464,7 @@ function run($surveyid,$args) {
                     // Link to Public statistics  **********
                     if ($thissurvey['publicstatistics'] == 'Y')
                     {
-                        $url = Yii::app()->getController()->createUrl("statistics_user/sid/{$surveyid}/lang/".$_SESSION['survey_'.$surveyid]['s_lang']);
+                        $url = Yii::app()->getController()->createUrl("statistics_user/sid/{$surveyid}/lang/".$_SESSION[$LEMsessid]['s_lang']);
                         $completed .= "<br /><br />"
                         . "<a class='publicstatisticslink' href='$url' target='_blank'>"
                         . $clang->gT("View the statistics for this survey.")
@@ -471,8 +472,8 @@ function run($surveyid,$args) {
                     }
                     //*****************************************
 
-                    $_SESSION['survey_'.$surveyid]['finished'] = true;
-                    $_SESSION['survey_'.$surveyid]['sid'] = $surveyid;
+                    $_SESSION[$LEMsessid]['finished'] = true;
+                    $_SESSION[$LEMsessid]['sid'] = $surveyid;
 
                     sendCacheHeaders();
                     if (isset($thissurvey['autoredirect']) && $thissurvey['autoredirect'] == "Y" && $thissurvey['surveyls_url'])
@@ -529,7 +530,7 @@ function run($surveyid,$args) {
             doFooter();
             exit;
         }
-        createFieldMap($surveyid,'full',false,false,$_SESSION['survey_'.$surveyid]['s_lang']);
+        createFieldMap($surveyid,'full',false,false,$_SESSION[$LEMsessid]['s_lang']);
         //GET GROUP DETAILS
 
         if ($surveyMode == 'group' && $previewgrp)
@@ -552,7 +553,7 @@ function run($surveyid,$args) {
             }
             if (isset($moveResult))
             {
-                $_SESSION['survey_'.$surveyid]['step'] = $moveResult['seq'] + 1;  // step is index base 1?
+                $_SESSION[$LEMsessid]['step'] = $moveResult['seq'] + 1;  // step is index base 1?
             }
 
             $stepInfo = LimeExpressionManager::GetStepIndexInfo($moveResult['seq']);
@@ -562,7 +563,7 @@ function run($surveyid,$args) {
         }
         else
         {
-            if (($show_empty_group) || !isset($_SESSION['survey_'.$surveyid]['grouplist']))
+            if (($show_empty_group) || !isset($_SESSION[$LEMsessid]['grouplist']))
             {
                 $gid = -1; // Make sure the gid is unused. This will assure that the foreach (fieldarray as ia) has no effect.
                 $groupname = $clang->gT("Submit your answers");
@@ -587,12 +588,12 @@ function run($surveyid,$args) {
         }
         if ($previewquestion)
         {
-            $_SESSION['survey_'.$surveyid]['step'] = 0; //maybe unset it after the question has been displayed?
+            $_SESSION[$LEMsessid]['step'] = 0; //maybe unset it after the question has been displayed?
         }
 
-        if ($_SESSION['survey_'.$surveyid]['step'] > $_SESSION['survey_'.$surveyid]['maxstep'])
+        if ($_SESSION[$LEMsessid]['step'] > $_SESSION[$LEMsessid]['maxstep'])
         {
-            $_SESSION['survey_'.$surveyid]['maxstep'] = $_SESSION['survey_'.$surveyid]['step'];
+            $_SESSION[$LEMsessid]['maxstep'] = $_SESSION[$LEMsessid]['step'];
         }
 
         // If the survey uses answer persistence and a srid is registered in SESSION
@@ -600,7 +601,7 @@ function run($surveyid,$args) {
         /* Only survey mode used this - should all?
         if ($thissurvey['tokenanswerspersistence'] == 'Y' &&
         $thissurvey['anonymized'] == "N" &&
-        isset($_SESSION['srid']) &&
+        isset($_SESSION[$LEMsessid]['srid']) &&
         $thissurvey['active'] == "Y")
         {
         loadanswers();
@@ -611,7 +612,7 @@ function run($surveyid,$args) {
         //PRESENT SURVEY
         //******************************************************************************************************
 
-        $okToShowErrors = (!$previewgrp && (isset($invalidLastPage) || $_SESSION['survey_'.$surveyid]['prevstep'] == $_SESSION['survey_'.$surveyid]['step']));
+        $okToShowErrors = (!$previewgrp && (isset($invalidLastPage) || $_SESSION[$LEMsessid]['prevstep'] == $_SESSION[$LEMsessid]['step']));
 
         Yii::app()->getController()->loadHelper('qanda');
         setNoAnswerMode($thissurvey);
@@ -619,7 +620,7 @@ function run($surveyid,$args) {
         //Iterate through the questions about to be displayed:
         $inputnames = array();
 
-        foreach ($_SESSION['survey_'.$surveyid]['grouplist'] as $gl)
+        foreach ($_SESSION[$LEMsessid]['grouplist'] as $gl)
         {
             $gid = $gl[0];
             $qnumber = 0;
@@ -634,7 +635,7 @@ function run($surveyid,$args) {
             }
 
             // TMSW - could iterate through LEM::currentQset instead
-            foreach ($_SESSION['survey_'.$surveyid]['fieldarray'] as $key => $ia)
+            foreach ($_SESSION[$LEMsessid]['fieldarray'] as $key => $ia)
             {
                 ++$qnumber;
                 $ia[9] = $qnumber; // incremental question count;
@@ -694,16 +695,16 @@ function run($surveyid,$args) {
         {
             if ($show_empty_group)
             {
-                $percentcomplete = makegraph($_SESSION['survey_'.$surveyid]['totalsteps'] + 1, $_SESSION['survey_'.$surveyid]['totalsteps']);
+                $percentcomplete = makegraph($_SESSION[$LEMsessid]['totalsteps'] + 1, $_SESSION[$LEMsessid]['totalsteps']);
             }
             else
             {
-                $percentcomplete = makegraph($_SESSION['survey_'.$surveyid]['step'], $_SESSION['survey_'.$surveyid]['totalsteps']);
+                $percentcomplete = makegraph($_SESSION[$LEMsessid]['step'], $_SESSION[$LEMsessid]['totalsteps']);
             }
         }
         if (!(isset($languagechanger) && strlen($languagechanger) > 0) && function_exists('makeLanguageChangerSurvey'))
         {
-            $languagechanger = makeLanguageChangerSurvey($_SESSION['survey_'.$surveyid]['s_lang']);
+            $languagechanger = makeLanguageChangerSurvey($_SESSION[$LEMsessid]['s_lang']);
         }
 
         //READ TEMPLATES, INSERT DATA AND PRESENT PAGE
@@ -728,14 +729,14 @@ function run($surveyid,$args) {
         echo templatereplace(file_get_contents("$thistpl/startpage.pstpl"), array(), $redata);
 
         //ALTER PAGE CLASS TO PROVIDE WHOLE-PAGE ALTERNATION
-        if ($surveyMode != 'survey' && $_SESSION['survey_'.$surveyid]['step'] != $_SESSION['survey_'.$surveyid]['prevstep'] ||
-        (isset($_SESSION['survey_'.$surveyid]['stepno']) && $_SESSION['survey_'.$surveyid]['stepno'] % 2))
+        if ($surveyMode != 'survey' && $_SESSION[$LEMsessid]['step'] != $_SESSION[$LEMsessid]['prevstep'] ||
+        (isset($_SESSION[$LEMsessid]['stepno']) && $_SESSION[$LEMsessid]['stepno'] % 2))
         {
-            if (!isset($_SESSION['survey_'.$surveyid]['stepno']))
-                $_SESSION['survey_'.$surveyid]['stepno'] = 0;
-            if ($_SESSION['survey_'.$surveyid]['step'] != $_SESSION['survey_'.$surveyid]['prevstep'])
-                ++$_SESSION['survey_'.$surveyid]['stepno'];
-            if ($_SESSION['survey_'.$surveyid]['stepno'] % 2)
+            if (!isset($_SESSION[$LEMsessid]['stepno']))
+                $_SESSION[$LEMsessid]['stepno'] = 0;
+            if ($_SESSION[$LEMsessid]['step'] != $_SESSION[$LEMsessid]['prevstep'])
+                ++$_SESSION[$LEMsessid]['stepno'];
+            if ($_SESSION[$LEMsessid]['stepno'] % 2)
             {
                 echo "<script type=\"text/javascript\">\n"
                 . "  $(\"body\").addClass(\"page-odd\");\n"
@@ -886,7 +887,7 @@ function checkconditions(value, name, type, evt_type)
             echo "<p><span class='errormandatory'>" . $clang->gT("One or more uploaded files are not in proper format/size. You cannot proceed until these files are valid.") . "</span></p>";
         }
 
-        foreach ($_SESSION['survey_'.$surveyid]['grouplist'] as $gl)
+        foreach ($_SESSION[$LEMsessid]['grouplist'] as $gl)
         {
             $gid = $gl[0];
             $groupname = $gl[1];
@@ -934,7 +935,7 @@ function checkconditions(value, name, type, evt_type)
                     $man_class .= ' mandatory';
                 }
 
-                if ($qinfo['anyUnanswered'] && $_SESSION['survey_'.$surveyid]['maxstep'] != $_SESSION['survey_'.$surveyid]['step'])
+                if ($qinfo['anyUnanswered'] && $_SESSION[$LEMsessid]['maxstep'] != $_SESSION[$LEMsessid]['step'])
                 {
                     $man_class .= ' missing';
                 }
@@ -1029,7 +1030,7 @@ function checkconditions(value, name, type, evt_type)
                 $lastGseq=-1;
                 $gseq = -1;
                 $grel = true;
-                for($v = 0, $n = 0; $n != $_SESSION['survey_'.$surveyid]['maxstep']; ++$n)
+                for($v = 0, $n = 0; $n != $_SESSION[$LEMsessid]['maxstep']; ++$n)
                 {
                     if (!isset($stepIndex[$n])) {
                         continue;   // this is an invalid group - skip it
@@ -1041,7 +1042,7 @@ function checkconditions(value, name, type, evt_type)
                         if ($lastGseq != $stepInfo['gseq']) {
                             // show the group label
                             ++$gseq;
-                            $g = $_SESSION['survey_'.$surveyid]['grouplist'][$gseq];
+                            $g = $_SESSION[$LEMsessid]['grouplist'][$gseq];
                             $grel = !LimeExpressionManager::GroupIsIrrelevantOrHidden($stepInfo['gid']);
                             if ($grel)
                             {
@@ -1053,7 +1054,7 @@ function checkconditions(value, name, type, evt_type)
                         {
                             continue;
                         }
-                        $q = $_SESSION['survey_'.$surveyid]['fieldarray'][$n];
+                        $q = $_SESSION[$LEMsessid]['fieldarray'][$n];
                     }
                     else
                     {
@@ -1062,7 +1063,7 @@ function checkconditions(value, name, type, evt_type)
                         {
                             continue;
                         }
-                        $g = $_SESSION['survey_'.$surveyid]['grouplist'][$gseq];
+                        $g = $_SESSION[$LEMsessid]['grouplist'][$gseq];
                     }
 
                     $sText = (($surveyMode == 'group') ? flattenText($g[1]) : flattenText($q[3]));
@@ -1070,7 +1071,7 @@ function checkconditions(value, name, type, evt_type)
 
                     ++$v;
 
-                    $class = ($n == $_SESSION['survey_'.$surveyid]['step'] - 1 ? 'current' : ($bGAnsw ? 'answer' : 'missing'));
+                    $class = ($n == $_SESSION[$LEMsessid]['step'] - 1 ? 'current' : ($bGAnsw ? 'answer' : 'missing'));
                     if ($v % 2)
                         $class .= " odd";
 
@@ -1078,7 +1079,7 @@ function checkconditions(value, name, type, evt_type)
                     echo "<div class=\"row $class\" onclick=\"javascript:document.limesurvey.move.value = '$s'; document.limesurvey.submit();\"><span class=\"hdr\">$v</span><span title=\"$sText\">$sText</span></div>";
                 }
 
-                if ($_SESSION['survey_'.$surveyid]['maxstep'] == $_SESSION['survey_'.$surveyid]['totalsteps'])
+                if ($_SESSION[$LEMsessid]['maxstep'] == $_SESSION[$LEMsessid]['totalsteps'])
                 {
                     echo "<input class='submit' type='submit' accesskey='l' onclick=\"javascript:document.limesurvey.move.value = 'movesubmit';\" value=' "
                     . $clang->gT("Submit") . " ' name='move2' />\n";
@@ -1095,11 +1096,11 @@ function checkconditions(value, name, type, evt_type)
                 echo "\n";
             }
 
-            echo "<input type='hidden' name='thisstep' value='{$_SESSION['survey_'.$surveyid]['step']}' id='thisstep' />\n";
+            echo "<input type='hidden' name='thisstep' value='{$_SESSION[$LEMsessid]['step']}' id='thisstep' />\n";
             echo "<input type='hidden' name='sid' value='$surveyid' id='sid' />\n";
             echo "<input type='hidden' name='start_time' value='" . time() . "' id='start_time' />\n";
-            $_SESSION['survey_'.$surveyid]['LEMpostKey'] = mt_rand();
-            echo "<input type='hidden' name='LEMpostKey' value='{$_SESSION['survey_'.$surveyid]['LEMpostKey']}' id='LEMpostKey' />\n";
+            $_SESSION[$LEMsessid]['LEMpostKey'] = mt_rand();
+            echo "<input type='hidden' name='LEMpostKey' value='{$_SESSION[$LEMsessid]['LEMpostKey']}' id='LEMpostKey' />\n";
 
             if (isset($token) && !empty($token))
             {
diff --git a/application/helpers/expressions/em_core_helper.php b/application/helpers/expressions/em_core_helper.php
index 03209f33d76..5b5bc343738 100644
--- a/application/helpers/expressions/em_core_helper.php
+++ b/application/helpers/expressions/em_core_helper.php
@@ -2839,11 +2839,13 @@ static function UnitTestEvaluator()
         $em = new ExpressionManager();
         $LEM->setTempVars($vars);
 
+        $LEMsessid = 'survey_' . Yii::app()->getConfig('surveyID');
+
         // manually set relevance status
-        $_SESSION['relevanceStatus'] = array();
+        $_SESSION[$LEMsessid]['relevanceStatus'] = array();
         foreach ($vars as $var) {
             if (isset($var['qseq'])) {
-                $_SESSION['relevanceStatus'][$var['qseq']] = 1;
+                $_SESSION[$LEMsessid]['relevanceStatus'][$var['qseq']] = 1;
             }
         }
 
diff --git a/application/helpers/expressions/em_manager_helper.php b/application/helpers/expressions/em_manager_helper.php
index 77116e81543..044a4ded464 100644
--- a/application/helpers/expressions/em_manager_helper.php
+++ b/application/helpers/expressions/em_manager_helper.php
@@ -35,6 +35,7 @@ class LimeExpressionManager {
     private $em;    // Expression Manager
     private $groupRelevanceInfo;
     private $sid;
+    private $sessid;    // session name
     private $groupNum;
     private $debugLevel=0;  // sum of LEM_DEBUG constants - use bitwise AND comparisons to identify which parts to use
     private $knownVars; // collection of variable attributes, indexed by SGQA code
@@ -2348,14 +2349,14 @@ private function setVariableAndTokenMappingsForExpressionManager($surveyid,$forc
         $this->q2subqInfo = $q2subqInfo;
 
         // Now set tokens
-        if (isset($_SESSION['token']) && $_SESSION['token'] != '')
+        if (isset($_SESSION[$this->sessid]['token']) && $_SESSION[$this->sessid]['token'] != '')
         {
             //Gather survey data for tokenised surveys, for use in presenting questions
-            $_SESSION['thistoken']=getTokenData($surveyid, $_SESSION['token']);
+            $_SESSION[$this->sessid]['thistoken']=getTokenData($surveyid, $_SESSION[$this->sessid]['token']);
         }
-        if (isset($_SESSION['thistoken']))
+        if (isset($_SESSION[$this->sessid]['thistoken']))
         {
-            foreach (array_keys($_SESSION['thistoken']) as $tokenkey)
+            foreach (array_keys($_SESSION[$this->sessid]['thistoken']) as $tokenkey)
             {
                 if ($anonymized)
                 {
@@ -2363,7 +2364,7 @@ private function setVariableAndTokenMappingsForExpressionManager($surveyid,$forc
                 }
                 else
                 {
-                    $val = $_SESSION['thistoken'][$tokenkey];
+                    $val = $_SESSION[$this->sessid]['thistoken'][$tokenkey];
                 }
                 $key = "TOKEN:" . strtoupper($tokenkey);
                 $this->knownVars[$key] = array(
@@ -2443,12 +2444,12 @@ static function SubQuestionIsRelevant($sgqa)
         $sqrel=1;
         if (isset($var['rowdivid']) && $var['rowdivid'] != '')
         {
-            $sqrel = (isset($_SESSION['relevanceStatus'][$var['rowdivid']]) ? $_SESSION['relevanceStatus'][$var['rowdivid']] : 1);
+            $sqrel = (isset($_SESSION[$LEM->sessid]['relevanceStatus'][$var['rowdivid']]) ? $_SESSION[$LEM->sessid]['relevanceStatus'][$var['rowdivid']] : 1);
         }
         $qid = $var['qid'];
-        $qrel = (isset($_SESSION['relevanceStatus'][$qid]) ? $_SESSION['relevanceStatus'][$qid] : 1);
+        $qrel = (isset($_SESSION[$LEM->sessid]['relevanceStatus'][$qid]) ? $_SESSION[$LEM->sessid]['relevanceStatus'][$qid] : 1);
         $gid = $var['gid'];
-        $grel = (isset($_SESSION['relevanceStatus']['G' . $gid]) ? $_SESSION['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
+        $grel = (isset($_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid]) ? $_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
         return ($grel && $qrel && $sqrel);
     }
 
@@ -2460,10 +2461,10 @@ static function SubQuestionIsRelevant($sgqa)
     static function QuestionIsRelevant($qid)
     {
         $LEM =& LimeExpressionManager::singleton();
-        $qrel = (isset($_SESSION['relevanceStatus'][$qid]) ? $_SESSION['relevanceStatus'][$qid] : 1);
+        $qrel = (isset($_SESSION[$LEM->sessid]['relevanceStatus'][$qid]) ? $_SESSION[$LEM->sessid]['relevanceStatus'][$qid] : 1);
         $groupSeq = (isset($LEM->questionId2groupSeq[$qid]) ? $LEM->questionId2groupSeq[$qid] : -1);
         $gid = (isset($LEM->gseq2info[$groupSeq]['gid']) ? $LEM->gseq2info[$groupSeq]['gid'] : -1);
-        $grel = (isset($_SESSION['relevanceStatus']['G' . $gid]) ? $_SESSION['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
+        $grel = (isset($_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid]) ? $_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
         return ($grel && $qrel);
     }
 
@@ -2475,7 +2476,7 @@ static function QuestionIsRelevant($qid)
     static function GroupIsIrrelevantOrHidden($gid)
     {
         $LEM =& LimeExpressionManager::singleton();
-        $grel = (isset($_SESSION['relevanceStatus']['G' . $gid]) ? $_SESSION['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
+        $grel = (isset($_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid]) ? $_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid] : 1);   // group-level relevance based upon grelevance equation
         $gseq = (isset($LEM->groupId2groupSeq[$gid]) ? $LEM->groupId2groupSeq[$gid] : -1);
         $gshow = (isset($LEM->indexGseq[$gseq]['show']) ? $LEM->indexGseq[$gseq]['show'] : true);   // default to true?
         return !($grel && $gshow);
@@ -2512,7 +2513,7 @@ function ProcessAllNeededRelevance($onlyThisQseq=NULL)
                     $rel['type'],
                     $rel['hidden']
                     );
-            $_SESSION['relevanceStatus'][$qid] = $result;
+            $_SESSION[$this->sessid]['relevanceStatus'][$qid] = $result;
 
             if (!isset($grelComputed[$gid])) {
                 $this->_ProcessGroupRelevance($gid);
@@ -2813,7 +2814,7 @@ private function _ProcessGroupRelevance($gid)
                 'prettyprint'=> $prettyPrint,
                 'hasErrors' => $hasErrors,
             );
-            $_SESSION['relevanceStatus']['G' . $gid] = $result;
+            $_SESSION[$this->sessid]['relevanceStatus']['G' . $gid] = $result;
         }
     }
 
@@ -2857,6 +2858,7 @@ static function StartSurvey($surveyid,$surveyMode='group',$options=NULL,$forceRe
     {
         $LEM =& LimeExpressionManager::singleton();
         $LEM->sid=sanitize_int($surveyid);
+        $LEM->sessid = 'survey_' . $LEM->sid;
 
         if (is_null($options)) {
             $options = array();
@@ -2882,7 +2884,7 @@ static function StartSurvey($surveyid,$surveyMode='group',$options=NULL,$forceRe
         $LEM->surveyOptions['token'] = (isset($options['token']) ? $options['token'] : NULL);
 
         $LEM->debugLevel=$debugLevel;
-        $_SESSION['LEMdebugLevel']=$debugLevel; // need acces to SESSSION to decide whether to cache serialized instance of $LEM
+        $_SESSION[$LEM->sessid]['LEMdebugLevel']=$debugLevel; // need acces to SESSSION to decide whether to cache serialized instance of $LEM
         switch ($surveyMode) {
             case 'survey':
                 $LEM->allOnOnePage=true;
@@ -2905,9 +2907,9 @@ static function StartSurvey($surveyid,$surveyMode='group',$options=NULL,$forceRe
         $LEM->indexGseq=array();
         $LEM->indexQseq=array();
         
-        if (isset($_SESSION['survey_'.$surveyid]['startingValues']) && is_array($_SESSION['survey_'.$surveyid]['startingValues']) && count($_SESSION['survey_'.$surveyid]['startingValues']) > 0)
+        if (isset($_SESSION[$LEM->sessid]['startingValues']) && is_array($_SESSION[$LEM->sessid]['startingValues']) && count($_SESSION[$LEM->sessid]['startingValues']) > 0)
         {
-            $startingValues = $_SESSION['survey_'.$surveyid]['startingValues'];
+            $startingValues = $_SESSION[$LEM->sessid]['startingValues'];
             $LEM->_UpdateValuesInDatabase($startingValues);
         }
 
@@ -3275,8 +3277,8 @@ static function NavigateForwards($force=false) {
     private function _UpdateValuesInDatabase($updatedValues, $finished=false)
     {
         $message = '';
-        $_SESSION['datestamp']=dateShift(date("Y-m-d H:i:s"), "Y-m-d H:i:s", $this->surveyOptions['timeadjust']);
-        if ($this->surveyOptions['active'] && !isset($_SESSION['srid']))
+        $_SESSION[$this->sessid]['datestamp']=dateShift(date("Y-m-d H:i:s"), "Y-m-d H:i:s", $this->surveyOptions['timeadjust']);
+        if ($this->surveyOptions['active'] && !isset($_SESSION[$this->sessid]['srid']))
         {
             // Create initial insert row for this record
             $today = dateShift(date("Y-m-d H:i:s"), "Y-m-d H:i:s", $this->surveyOptions['timeadjust']);
@@ -3285,9 +3287,9 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
                 //"ipaddr"=>(($this->surveyOptions['ipaddr'] && isset($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : ''),
                 "startlanguage"=>$this->surveyOptions['startlanguage'],
                 //"token"=>($this->surveyOptions['token']),
-                //"datestamp"=>($this->surveyOptions['datestamp'] ? $_SESSION['datestamp'] : NULL),
+                //"datestamp"=>($this->surveyOptions['datestamp'] ? $_SESSION[$this->sessid]['datestamp'] : NULL),
                 //"refurl"=>(($this->surveyOptions['refurl']) ? getenv("HTTP_REFERER") : NULL),
-                //"startdate"=>($this->surveyOptions['datestamp'] ? $_SESSION['datestamp'] : date("Y-m-d H:i:s",0)),
+                //"startdate"=>($this->surveyOptions['datestamp'] ? $_SESSION[$LEM->sessid]['datestamp'] : date("Y-m-d H:i:s",0)),
                 );
             if ($this->surveyOptions['anonymized'] == "N")
             {
@@ -3296,8 +3298,8 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
             if ($this->surveyOptions['datestamp'] == "Y")
             {
                 $sdata = array_merge($sdata, array(
-                                            "datestamp"=>($this->surveyOptions['datestamp'] ? $_SESSION['datestamp'] : NULL),
-                                            "startdate"=>($this->surveyOptions['datestamp'] ? $_SESSION['datestamp'] : date("Y-m-d H:i:s",0))
+                                            "datestamp"=>($this->surveyOptions['datestamp'] ? $_SESSION[$this->sessid]['datestamp'] : NULL),
+                                            "startdate"=>($this->surveyOptions['datestamp'] ? $_SESSION[$this->sessid]['datestamp'] : date("Y-m-d H:i:s",0))
                                                 ));
         
             }
@@ -3314,7 +3316,7 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
             if (Yii::app()->db->createCommand()->insert($this->surveyOptions['tablename'], $sdata))    // Checked
             {
                 $srid = Yii::app()->db->getLastInsertID();
-                $_SESSION['srid'] = $srid;
+                $_SESSION[$this->sessid]['srid'] = $srid;
             }
             else
             {
@@ -3356,14 +3358,14 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
             }
             $setter[] = dbQuoteID('lastpage') . "=" . dbQuoteAll($thisstep);
 
-            if ($this->surveyOptions['datestamp'] && isset($_SESSION['datestamp'])) {
-                $setter[] = dbQuoteID('datestamp') . "=" . dbQuoteAll($_SESSION['datestamp']);
+            if ($this->surveyOptions['datestamp'] && isset($_SESSION[$this->sessid]['datestamp'])) {
+                $setter[] = dbQuoteID('datestamp') . "=" . dbQuoteAll($_SESSION[$this->sessid]['datestamp']);
             }
             if ($this->surveyOptions['ipaddr'] && isset($_SERVER['REMOTE_ADDR'])) {
                 $setter[] = dbQuoteID('ipaddr') . "=" . dbQuoteAll($_SERVER['REMOTE_ADDR']);
             }
             if ($finished) {
-                $setter[] = dbQuoteID('submitdate') . "=" . dbQuoteAll($_SESSION['datestamp']);
+                $setter[] = dbQuoteID('submitdate') . "=" . dbQuoteAll($_SESSION[$this->sessid]['datestamp']);
             }
 
             foreach ($updatedValues as $key=>$value)
@@ -3402,9 +3404,9 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
             $query .= implode(', ', $setter);
             $query .= " WHERE ID=";
 
-            if (isset($_SESSION['srid']) && $this->surveyOptions['active'])
+            if (isset($_SESSION[$this->sessid]['srid']) && $this->surveyOptions['active'])
             {
-                $query .= $_SESSION['srid'];
+                $query .= $_SESSION[$this->sessid]['srid'];
 
                 if (!dbExecuteAssoc($query))
                 {
@@ -3424,7 +3426,7 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
                 if ($finished)
                 {
                     // Delete the save control record if successfully finalize the submission
-                    $query = "DELETE FROM {{saved_control}} where srid=".$_SESSION['srid'].' and sid='.$this->sid;
+                    $query = "DELETE FROM {{saved_control}} where srid=".$_SESSION[$this->sessid]['srid'].' and sid='.$this->sid;
                     Yii::app()->db->createCommand($query)->execute();
 
                     if (($this->debugLevel & LEM_DEBUG_VALIDATION_SUMMARY) == LEM_DEBUG_VALIDATION_SUMMARY) {
@@ -3451,9 +3453,9 @@ private function _UpdateValuesInDatabase($updatedValues, $finished=false)
                         check_quota('enforce',$this->sid);  // will create a page and quit.
                     }
                 }
-                else if ($this->surveyOptions['allowsave'] && isset($_SESSION['scid']))
+                else if ($this->surveyOptions['allowsave'] && isset($_SESSION[$this->sessid]['scid']))
                 {
-                    Saved_control::model()->updateByPk($_SESSION['scid'], array('saved_thisstep'=>$thisstep));
+                    Saved_control::model()->updateByPk($_SESSION[$this->sessid]['scid'], array('saved_thisstep'=>$thisstep));
                 }
             }
             if (($this->debugLevel & LEM_DEBUG_VALIDATION_SUMMARY) == LEM_DEBUG_VALIDATION_SUMMARY) {
@@ -3980,7 +3982,7 @@ function _ValidateGroup($groupSeq)
      * (a) mandatory - if so, then all relevant sub-questions must be answered (e.g. pay attention to array_filter and array_filter_exclude)
      * (b) always-hidden
      * (c) relevance status - including sub-question-level relevance
-     * (d) answered - if $_SESSION[sgqa]=='' or NULL, then it is not answered
+     * (d) answered - if $_SESSION[$LEM->sessid][sgqa]=='' or NULL, then it is not answered
      * (e) validity - whether relevant questions pass their validity tests
      * @param <type> $questionSeq - the 0-index sequence number for this question
      * @return <array> of information about this question and its sub-questions
@@ -4104,12 +4106,12 @@ function _ValidateQuestion($questionSeq)
                                 if ($sqrel)
                                 {
                                     $relevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=true;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=true;
                                 }
                                 else
                                 {
                                     $irrelevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=false;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=false;
                                 }
                             }
                             break;
@@ -4145,12 +4147,12 @@ function _ValidateQuestion($questionSeq)
                                 if ($sqrel)
                                 {
                                     $relevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=true;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=true;
                                 }
                                 else
                                 {
                                     $irrelevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=false;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=false;
                                 }
                             }
                         case 'A': //ARRAY (5 POINT CHOICE) radio-buttons
@@ -4191,12 +4193,12 @@ function _ValidateQuestion($questionSeq)
                                 if ($sqrel)
                                 {
                                     $relevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=true;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=true;
                                 }
                                 else
                                 {
                                     $irrelevantSQs[] = $sgqa;
-                                    $_SESSION['relevanceStatus'][$sq['rowdivid']]=false;
+                                    $_SESSION[$LEM->sessid]['relevanceStatus'][$sq['rowdivid']]=false;
                                 }
                             }
                             break;
@@ -4266,7 +4268,7 @@ function _ValidateQuestion($questionSeq)
         $unansweredSQs = array();   // list of sub-questions that weren't answered
         foreach ($relevantSQs as $sgqa)
         {
-            if (($qInfo['type'] != '*') && (!isset($_SESSION[$sgqa]) || ($_SESSION[$sgqa] === '' || is_null($_SESSION[$sgqa]))))
+            if (($qInfo['type'] != '*') && (!isset($_SESSION[$LEM->sessid][$sgqa]) || ($_SESSION[$LEM->sessid][$sgqa] === '' || is_null($_SESSION[$LEM->sessid][$sgqa]))))
             {
                 // then a relevant, visible, mandatory question hasn't been answered
                 // Equations are ignored, since set automatically
@@ -4542,7 +4544,7 @@ function _ValidateQuestion($questionSeq)
             $sgqas = explode('|',$LEM->qid2code[$qid]);
             foreach ($sgqas as $sgqa)
             {
-                $_SESSION[$sgqa] = NULL;
+                $_SESSION[$LEM->sessid][$sgqa] = NULL;
                 $updatedValues[$sgqa] = NULL;
             }
         }
@@ -4552,7 +4554,7 @@ function _ValidateQuestion($questionSeq)
             $result = flattenText($LEM->ProcessString($qInfo['eqn'], $qInfo['qid'],NULL,false,1,1,false,false));
             $sgqa = $LEM->qid2code[$qid];   // there will be only one, since Equation
             // Store the result of the Equation in the SESSION
-            $_SESSION[$sgqa] = $result;
+            $_SESSION[$LEM->sessid][$sgqa] = $result;
             $updatedValues[$sgqa] = array(
                 'type'=>'*',
                 'value'=>$result,
@@ -4566,19 +4568,19 @@ function _ValidateQuestion($questionSeq)
         foreach ($irrelevantSQs as $sq)
         {
             // NULL irrelevant sub-questions
-            $_SESSION[$sq] = NULL;
+            $_SESSION[$LEM->sessid][$sq] = NULL;
             $updatedValues[$sq] = NULL;
         }
 
-        // Regardless of whether relevant or hidden, if there is a default value and $_SESSION[$sgqa] is NULL, then use the default value in $_SESSION, but don't write to database
+        // Regardless of whether relevant or hidden, if there is a default value and $_SESSION[$LEM->sessid][$sgqa] is NULL, then use the default value in $_SESSION, but don't write to database
         // Also, set this AFTER testing relevance
         $sgqas = explode('|',$LEM->qid2code[$qid]);
         foreach ($sgqas as $sgqa)
         {
-            if (!is_null($LEM->knownVars[$sgqa]['default']) && !isset($_SESSION[$sgqa])) {
+            if (!is_null($LEM->knownVars[$sgqa]['default']) && !isset($_SESSION[$LEM->sessid][$sgqa])) {
                 // add support for replacements
                 $defaultVal = $LEM->ProcessString($LEM->knownVars[$sgqa]['default'], NULL, NULL, false, 1, 1, false, false, true);
-                $_SESSION[$sgqa] = $defaultVal;
+                $_SESSION[$LEM->sessid][$sgqa] = $defaultVal;
             }
         }
 
@@ -4638,7 +4640,7 @@ function _ValidateQuestion($questionSeq)
             'valid' => $qvalid,
         );
 
-        $_SESSION['relevanceStatus'][$qid] = $qrel;
+        $_SESSION[$LEM->sessid]['relevanceStatus'][$qid] = $qrel;
 
         return $qStatus;
     }
@@ -5418,7 +5420,7 @@ static function GetRelevanceAndTailoringJavaScript()
                         }
                         $undeclaredJsVars[] = $jsVar;
                         $sgqa = $knownVar['sgqa'];
-                        $codeValue = (isset($_SESSION[$sgqa])) ? $_SESSION[$sgqa] : '';
+                        $codeValue = (isset($_SESSION[$LEM->sessid][$sgqa])) ? $_SESSION[$LEM->sessid][$sgqa] : '';
                         $undeclaredVal[$jsVar] = $codeValue;
 
                         if (isset($LEM->jsVar2qid[$jsVar])) {
@@ -5437,8 +5439,8 @@ static function GetRelevanceAndTailoringJavaScript()
         }
         foreach ($qidList as $qid)
         {
-            if (isset($_SESSION['relevanceStatus'])) {
-                $relStatus = (isset($_SESSION['relevanceStatus'][$qid]) ? $_SESSION['relevanceStatus'][$qid] : 1);
+            if (isset($_SESSION[$LEM->sessid]['relevanceStatus'])) {
+                $relStatus = (isset($_SESSION[$LEM->sessid]['relevanceStatus'][$qid]) ? $_SESSION[$LEM->sessid]['relevanceStatus'][$qid] : 1);
             }
             else {
                 $relStatus = 1;
@@ -5448,8 +5450,8 @@ static function GetRelevanceAndTailoringJavaScript()
 
         foreach ($gidList as $gid)
         {
-            if (isset($_SESSION['relevanceStatus'])) {
-                $relStatus = (isset($_SESSION['relevanceStatus']['G' . $gid]) ? $_SESSION['relevanceStatus']['G' . $gid] : 1);
+            if (isset($_SESSION[$LEM->sessid]['relevanceStatus'])) {
+                $relStatus = (isset($_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid]) ? $_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid] : 1);
             }
             else {
                 $relStatus = 1;
@@ -5569,12 +5571,12 @@ static function UnitTestProcessStringContainingExpressions()
 
         $LEM->questionId2questionSeq = array();
         $LEM->questionId2groupSeq = array();
-        $_SESSION['relevanceStatus'] = array();
+        $_SESSION[$LEM->sessid]['relevanceStatus'] = array();
         foreach ($vars as $var) {
             if (isset($var['qseq'])) {
                 $LEM->questionId2questionSeq[$var['qseq']] = $var['qseq'];
                 $LEM->questionId2groupSeq[$var['qseq']] = $var['gseq'];
-                $_SESSION['relevanceStatus'][$var['qseq']] = 1;
+                $_SESSION[$LEM->sessid]['relevanceStatus'][$var['qseq']] = 1;
             }
         }
 
@@ -6100,8 +6102,8 @@ static function ProcessCurrentResponses()
                 $gid = $qinfo['info']['gid'];
                 $relevant = (isset($_POST['relevance' . $qid]) ? ($_POST['relevance' . $qid] == 1) : false);
                 $grelevant = (isset($_POST['relevanceG' . $gid]) ? ($_POST['relevanceG' . $gid] == 1) : false);
-                $_SESSION['relevanceStatus'][$qid] = $relevant;
-                $_SESSION['relevanceStatus']['G' . $gid] = $grelevant;
+                $_SESSION[$LEM->sessid]['relevanceStatus'][$qid] = $relevant;
+                $_SESSION[$LEM->sessid]['relevanceStatus']['G' . $gid] = $grelevant;
                 foreach (explode('|',$qinfo['sgqa']) as $sq)
                 {
                     $sqrelevant=true;
@@ -6111,7 +6113,7 @@ static function ProcessCurrentResponses()
                         if ($rowdivid!='' && isset($_POST['relevance' . $rowdivid]))
                         {
                             $sqrelevant = ($_POST['relevance' . $rowdivid] == 1);
-                            $_SESSION['relevanceStatus'][$rowdivid] = $sqrelevant;
+                            $_SESSION[$LEM->sessid]['relevanceStatus'][$rowdivid] = $sqrelevant;
                         }
                     }
                     $type = $qinfo['info']['type'];
@@ -6181,7 +6183,7 @@ static function ProcessCurrentResponses()
                                 }
                                 break;
                         }
-                        $_SESSION[$sq] = $value;
+                        $_SESSION[$LEM->sessid][$sq] = $value;
                         $updatedValues[$sq] = array (
                         'type'=>$type,
                         'value'=>$value,
@@ -6189,7 +6191,7 @@ static function ProcessCurrentResponses()
                     }
                     else {  // irrelevant, so database will be NULLed separately
                         // Must unset the value, rather than setting to '', so that EM can re-use the default value as needed.
-                        unset($_SESSION[$sq]);
+                        unset($_SESSION[$LEM->sessid][$sq]);
                         $updatedValues[$sq] = array (
                         'type'=>$type,
                         'value'=>NULL,
@@ -6199,7 +6201,7 @@ static function ProcessCurrentResponses()
             }
             if (isset($_POST['timerquestion']))
             {
-                $_SESSION[$_POST['timerquestion']]=sanitize_float($_POST[$_POST['timerquestion']]);
+                $_SESSION[$LEM->sessid][$_POST['timerquestion']]=sanitize_float($_POST[$_POST['timerquestion']]);
             }
             return $updatedValues;
         }
@@ -6267,8 +6269,8 @@ private function _GetVarAttribute($name,$attr,$default,$gseq,$qseq)
                     return $var['code'];    // for static values like TOKEN
                 }
                 else {
-                    if (isset($_SESSION[$sgqa])) {
-                        return $_SESSION[$sgqa];
+                    if (isset($_SESSION[$this->sessid][$sgqa])) {
+                        return $_SESSION[$this->sessid][$sgqa];
                     }
                     if (isset($var['default']) && !is_null($var['default'])) {
                         return $var['default'];
@@ -6444,9 +6446,9 @@ private function _GetVarAttribute($name,$attr,$default,$gseq,$qseq)
                 if (isset($args[1]) && $args[1]=='NAOK') {
                     return 1;
                 }
-                $grel = (isset($_SESSION['relevanceStatus']['G'.$gid]) ? $_SESSION['relevanceStatus']['G'.$gid] : 1);   // true by default
-                $qrel = (isset($_SESSION['relevanceStatus'][$qid]) ? $_SESSION['relevanceStatus'][$qid] : 0);
-                $sqrel = (isset($_SESSION['relevanceStatus'][$rowdivid]) ? $_SESSION['relevanceStatus'][$rowdivid] : 1);    // true by default - only want false if a subquestion is irrelevant
+                $grel = (isset($_SESSION[$this->sessid]['relevanceStatus']['G'.$gid]) ? $_SESSION[$this->sessid]['relevanceStatus']['G'.$gid] : 1);   // true by default
+                $qrel = (isset($_SESSION[$this->sessid]['relevanceStatus'][$qid]) ? $_SESSION[$this->sessid]['relevanceStatus'][$qid] : 0);
+                $sqrel = (isset($_SESSION[$this->sessid]['relevanceStatus'][$rowdivid]) ? $_SESSION[$this->sessid]['relevanceStatus'][$rowdivid] : 1);    // true by default - only want false if a subquestion is irrelevant
                 return ($grel && $qrel && $sqrel);
             default:
                 print 'UNDEFINED ATTRIBUTE: ' . $attr . "<br/>\n";
diff --git a/application/helpers/frontend_helper.php b/application/helpers/frontend_helper.php
index 2986e77555a..7ce9a6264da 100644
--- a/application/helpers/frontend_helper.php
+++ b/application/helpers/frontend_helper.php
@@ -1187,6 +1187,8 @@ function sendSubmitNotifications($surveyid)
         
         if (!isset($_SESSION['survey_'.$surveyid]['srid']))
             $srid = null;
+        else
+            $srid = $_SESSION['survey_'.$surveyid]['srid'];
         $aReplacementVars['ADMINNAME'] = $thissurvey['adminname'];
         $aReplacementVars['ADMINEMAIL'] = $thissurvey['adminemail'];
         $aReplacementVars['VIEWRESPONSEURL']="{$homeurl}/admin.php?action=browse&sid={$surveyid}&subaction=id&id=".$srid;
@@ -2162,6 +2164,7 @@ function surveymover()
     global $surveyid, $presentinggroupdescription;
 
     $clang = Yii::app()->lang;
+    $LEMsessid = Yii::app()->getConfig('surveyID');
 
     $surveymover = "";
 
@@ -2216,7 +2219,7 @@ function surveymover()
         $surveymover .=  "\t<button class='submit' type='submit' accesskey='n' onclick=\"javascript:document.limesurvey.move.value = 'movenext';\"
         value='".$clang->gT("Next")."' name='move2' id=\"movenextbtn\" $disabled>".$clang->gT("Next")."</button>\n";
     }
-    if (($_SESSION['survey_'.$surveyid]['step'] && ($_SESSION['survey_'.$surveyid]['step'] == $_SESSION['survey_'.$surveyid]['totalsteps']) && !$presentinggroupdescription) || $thissurvey['format'] == 'A')
+    if (isset($_SESSION['survey_'.$surveyid]['step']) && ($_SESSION['survey_'.$surveyid]['step'] && ($_SESSION['survey_'.$surveyid]['step'] == $_SESSION['survey_'.$surveyid]['totalsteps']) && !$presentinggroupdescription) || $thissurvey['format'] == 'A')
     {
         $surveymover .= "\t<button class=\"submit\" type=\"submit\" accesskey=\"l\" onclick=\"javascript:document.limesurvey.move.value = 'movesubmit';\"
         value=\"".$clang->gT("Submit")."\" name=\"move2\" id=\"movesubmitbtn\" $disabled>".$clang->gT("Submit")."</button>\n";
@@ -2775,8 +2778,8 @@ function display_first_page() {
     if (isset($loadsecurity)) {
         echo "\n<input type='hidden' name='loadsecurity' value='$loadsecurity' id='loadsecurity' />\n";
     }
-    $_SESSION['LEMpostKey'] = mt_rand();
-    echo "<input type='hidden' name='LEMpostKey' value='{$_SESSION['LEMpostKey']}' id='LEMpostKey' />\n";
+    $_SESSION['survey_'.$surveyid]['LEMpostKey'] = mt_rand();
+    echo "<input type='hidden' name='LEMpostKey' value='{$_SESSION['survey_'.$surveyid]['LEMpostKey']}' id='LEMpostKey' />\n";
     echo "<input type='hidden' name='thisstep' id='thisstep' value='0' />\n";
     
     echo "\n</form>\n";
diff --git a/application/helpers/qanda_helper.php b/application/helpers/qanda_helper.php
index 6b5c82e586d..63122ac10b7 100644
--- a/application/helpers/qanda_helper.php
+++ b/application/helpers/qanda_helper.php
@@ -3226,7 +3226,7 @@ function do_multipleshorttext($ia)
                 if (isset($_SESSION['survey_'.Yii::app()->getConfig('surveyID')][$myfname]))
                 {
                     $dispVal = $_SESSION['survey_'.Yii::app()->getConfig('surveyID')][$myfname];
-                    if ($qidattributes['numbers_only']==1)
+                    if ($aQuestionAttributes['numbers_only']==1)
                     {
                         $dispVal = str_replace('.',$sSeperator,$dispVal);
                     }
@@ -3261,7 +3261,7 @@ function do_multipleshorttext($ia)
                 if (isset($_SESSION['survey_'.Yii::app()->getConfig('surveyID')][$myfname]))
                 {
                     $dispVal = $_SESSION['survey_'.Yii::app()->getConfig('surveyID')][$myfname];
-                    if ($qidattributes['numbers_only']==1)
+                    if ($aQuestionAttributes['numbers_only']==1)
                     {
                         $dispVal = str_replace('.',$sSeperator,$dispVal);
                     }
@@ -3935,7 +3935,7 @@ function do_shortfreetext($ia)
     else
     {
         $numbersonly = '';
-        $checkconditionFunction = "fixnum_checkconditions";
+        $checkconditionFunction = "checkconditions";
     }
     if (intval(trim($aQuestionAttributes['maximum_chars']))>0)
     {