Added some error checking to form limit plugin, to avoid cryptic SQL

error if the plugin is not set up correctly (like if the user element
hasn't been specified, which was tossing an SQL error).  Will not refuse
to load form, and enqueue an informative msg.

plugins/fabrik_form/limit/language/en-GB/en-GB.plg_fabrik_form_limit.ini

@@ -36,3 +36,5 @@ PLG_FORM_LIMIT_CONDITION_DESC="Optional PHP code. If code returns false, limit i
 ; front end
 PLG_FORM_LIMIT_ENTRIES_LEFT_MESSAGE="You have %s of %s entries remaining"
 PLG_FORM_LIMIT_LIMIT_REACHED="You have reached your limit of %s records"
+PLG_FORM_LIMIT_NOT_SETUP="The limit plugin is not set up correctly, cannot load form"
+

plugins/fabrik_form/limit/limit.php

@@ -62,6 +62,13 @@ private function _process()
 
 		$limit = $this->limit();
 		$c = $this->count();
+
+		if ($c === false)
+		{
+			JFactory::getApplication()->enqueueMessage(FText::_("PLG_FORM_LIMIT_NOT_SETUP"));
+
+			return false;
+		}
 
 		// Allow for unlimited
 		if ($limit == -1)
@@ -102,6 +109,11 @@ protected function count()
 		$fk = $params->get('limit_fk');
 		$fkVal = '';
 
+		if (empty($field))
+		{
+			return false;	
+		}
+
 		if (!empty($fk))
 		{
 			$fkVal = FArrayHelper::getValue(