Fixed issue #9064: Blank page/error on step 4 when updating from vers…

…ion 2.0

application/controllers/admin/update.php

@@ -457,9 +457,18 @@ function step4()
         setGlobalSetting('updateavailable','0');
         setGlobalSetting('updatebuild','');
         setGlobalSetting('updateversions','');
-        // We create this new language object here because the language files might have been overwritten earlier
-        // and the pointers to the file from the application language are not valid anymore 
-        Yii::app()->lang = $aData['clang'] = new Limesurvey_lang(Yii::app()->session['adminlang'],true);
+        // We redirect here because the  files might have been overwritten earlier
+        // and classes may have been changed that would be needed in the view
+        Yii::app()->session['installlstep4b']=$aData;
+        $this->redirect(array('/admin/update/sa/step4b'));
+    }
+
+
+    function step4b()
+    {
+        if (!isset(Yii::app()->session['installlstep4b'])) die();
+        $aData=Yii::app()->session['installlstep4b'];
+        unset (Yii::app()->session['installlstep4b']);
         $this->_renderWrappedTemplate('update', 'step4', $aData);
     }