diff --git a/README.md b/README.md
index 4415220fffaeb6173418f0902ece57882eae1fe8..d0463d6d847596d520913c6582519d263e7e6550 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # ILIAS FormATest
-* For ILIAS versions: 5.3.0 - 5.3.999
+* For ILIAS versions: 5.3.0 - 5.4.999
 
 ## Installation Instructions
 1. Clone this repository to <ILIAS_DIRECTORY>/Customizing/global/plugins/Services/Repository/RepositoryObject/FormATest
diff --git a/classes/class.ilFormATestExporter.php b/classes/class.ilFormATestExporter.php
index 9e7588ac18fb5ddc83438c5b084b6b90a1ab9372..aee500ed64605ea7e394deb6eda32a6c06995ca6 100755
--- a/classes/class.ilFormATestExporter.php
+++ b/classes/class.ilFormATestExporter.php
@@ -299,7 +299,7 @@ class ilFormATestExporter extends ilXmlExporter
 			$this->questions[$question['question_id']] = $question['question_id'];
 		}
 		$this->xml_writer->xmlEndTag('Questions');
-		if(count($this->questions) > 0)
+		if(is_array($this->questions) && count($this->questions) > 0)
 		{
 			$this->exportQuestions();
 		}
diff --git a/classes/class.ilFormATestImporter.php b/classes/class.ilFormATestImporter.php
index 4c3e1dbb1d2e511552ee6c35e9f0d7966cedd3cc..4f85b953e4fddb1752269864feb66db0f8b90c67 100644
--- a/classes/class.ilFormATestImporter.php
+++ b/classes/class.ilFormATestImporter.php
@@ -372,7 +372,7 @@ class ilFormATestImporter extends ilXmlImporter
 			$this->addNodeMapping($node_data[0]['NodeId'], $node->getId());
 			
 			$jump_conditions = $node_data['jump_conditions'];
-			if(count($jump_conditions) == 0)
+			if(is_array($jump_conditions) && count($jump_conditions) == 0)
 			{
 				continue 1;
 			}
diff --git a/classes/class.ilFormATestXmlValidator.php b/classes/class.ilFormATestXmlValidator.php
index 029ac28c059dc6564e4b18b79feaacccb1c6f905..1abe6db87d3ae375683788d4a61fe1923cb1799a 100644
--- a/classes/class.ilFormATestXmlValidator.php
+++ b/classes/class.ilFormATestXmlValidator.php
@@ -229,7 +229,7 @@ class ilFormATestXmlValidator
 			return true;
 		}
 		
-		if(count($this->errors))
+		if(is_array($this->errors) && count($this->errors))
 		{
 			return false;
 		}
@@ -275,7 +275,7 @@ class ilFormATestXmlValidator
 			}
 		}
 		libxml_clear_errors();
-		if(count($this->errors))
+		if(is_array($this->errors) && count($this->errors))
 		{
 			return false;
 		}
diff --git a/classes/class.ilObjFormATest.php b/classes/class.ilObjFormATest.php
index 544ad27a8f25a738c00abd9b3a75c9cec9a7d0db..f5e23247d734ac04c99715033d1b9ecaa667521f 100644
--- a/classes/class.ilObjFormATest.php
+++ b/classes/class.ilObjFormATest.php
@@ -1333,7 +1333,7 @@ class ilObjFormATest extends ilObjectPlugin implements ilLPStatusPluginInterface
 		global $DIC; 
 		$ilDB = $DIC->database();
 
-		if(count($obj_ids) == 1)
+		if(is_array($obj_ids) && count($obj_ids) == 1)
 		{
 			$in = ' id = ' . $ilDB->quote(current($obj_ids), 'integer') . ' ';
 		}
@@ -1378,11 +1378,12 @@ class ilObjFormATest extends ilObjectPlugin implements ilLPStatusPluginInterface
 	 */
 	final public function isComplete()
 	{
-		if(!count($this->mark_schema->mark_steps))
+		if(is_array($this->mark_schema->mark_steps) && !count($this->mark_schema->mark_steps))
 		{
 			return false;
 		}
 
+		if(is_array($this->getSetList()->getData()))
 		return count((array)$this->getSetList()->getData()) > 0;
 	}
 
diff --git a/classes/class.ilObjFormATestGUI.php b/classes/class.ilObjFormATestGUI.php
index 30640bccdbed86ae6085f9cfe49cae8041ff697b..c120bc5547246f6036eea1607d2b2f9b1098b56b 100644
--- a/classes/class.ilObjFormATestGUI.php
+++ b/classes/class.ilObjFormATestGUI.php
@@ -474,7 +474,7 @@ class ilObjFormATestGUI extends ilObjectPluginGUI implements ilDesktopItemHandli
 		$xqsp_available_pools = ilObjQuestionSetPool::getAvailableQuestionSetPools(TRUE);
 		$options_1 = array(ilFormATestImporter::SINGLE_IMPORT_NEW_POOL => $this->plugin->txt("new_xqsp_pool"));
 		
-		if (count($xqsp_available_pools))
+		if (is_array($xqsp_available_pools) && count($xqsp_available_pools))
 		{
 			foreach ($xqsp_available_pools as $key => $xqsp_obj)
 			{
@@ -498,7 +498,7 @@ class ilObjFormATestGUI extends ilObjectPluginGUI implements ilDesktopItemHandli
 			ilFormATestImporter::SINGLE_IMPORT_NO_POOL  => $this->lng->txt('assessment_no_pool')
 		);
 		
-		if (count($questionpools))
+		if (is_array($questionpools) && count($questionpools))
 		{
 			foreach ($questionpools as $key => $value)
 			{
diff --git a/classes/class.ilObjFormATestQuestionSetPoolGUI.php b/classes/class.ilObjFormATestQuestionSetPoolGUI.php
index 746391da5eda0c199c1a40e7f46052aa6c20827a..d45e4255ed0c552c947773668d4a70114ca2dd6d 100644
--- a/classes/class.ilObjFormATestQuestionSetPoolGUI.php
+++ b/classes/class.ilObjFormATestQuestionSetPoolGUI.php
@@ -90,26 +90,29 @@ class ilObjFormATestQuestionSetPoolGUI extends ilObjQuestionSetPoolGUI
 					$this->performCommand($cmd);
 
 					$reflection = new ReflectionClass(get_class($this->tpl));
-					$property = $reflection->getProperty('message');
+					$property   = $reflection->getProperty('message');
 					$property->setAccessible(true);
 					$values = $property->getValue($this->tpl);
 					$values = (array)$values;
 
-					if(ilObjQuestionSetPool::canSynchronizeSet($set->getOriginalId()))
+					if(is_array($values['failure']))
 					{
-						if(!strlen($_SESSION['failure']) && !count($values['failure']))
+						if(ilObjQuestionSetPool::canSynchronizeSet($set->getOriginalId()))
 						{
-							$ilCtrl->setParameter($this, "set_id", $set->getId());
-							$ilToolbar->setFormAction($ilCtrl->getFormAction($this));
-							$ilCtrl->setParameter($this, "set_id", "");
-							$ilToolbar->addFormButton($this->plugin->txt("synchronize_set"),"ilQuestionSetPoolSetsGUI.synchronize", "", true);
+							if(!strlen($_SESSION['failure']) && !count($values['failure']))
+							{
+								$ilCtrl->setParameter($this, "set_id", $set->getId());
+								$ilToolbar->setFormAction($ilCtrl->getFormAction($this));
+								$ilCtrl->setParameter($this, "set_id", "");
+								$ilToolbar->addFormButton($this->plugin->txt("synchronize_set"), "ilQuestionSetPoolSetsGUI.synchronize", "", true);
+							}
 						}
-					}
-					else
-					{
-						if(!strlen($_SESSION['failure']) && !count($values['failure']))
+						else
 						{
-							ilUtil::sendInfo($this->plugin->txt("not_in_test"));
+							if(!strlen($_SESSION['failure']) && !count($values['failure']))
+							{
+								ilUtil::sendInfo($this->plugin->txt("not_in_test"));
+							}
 						}
 					}
 				}
diff --git a/classes/controllers/abstract.ilXTSFControllerTableGUI.php b/classes/controllers/abstract.ilXTSFControllerTableGUI.php
index bbfab7995fb52e453e005578d8d58850168f75de..8f2d6210a660fad68024a1abdd0cd32195b71b72 100644
--- a/classes/controllers/abstract.ilXTSFControllerTableGUI.php
+++ b/classes/controllers/abstract.ilXTSFControllerTableGUI.php
@@ -19,6 +19,6 @@ abstract class ilXTSFControllerTableGUI extends ilXTSFControllerGUI
 	 */
 	protected function dataSelected($key)
 	{
-		return (isset($_POST[$key]) && count($_POST[$key]) > 0);
+		return (isset($_POST[$key]) && is_array($_POST[$key]) && count($_POST[$key]) > 0);
 	}
 }
diff --git a/classes/controllers/class.ilFormATestSetsGUI.php b/classes/controllers/class.ilFormATestSetsGUI.php
index f42019ebb718290674aff390da88d41e071d4082..53ca772f67220dc16f683a0d458d9dfb0e43cb16 100644
--- a/classes/controllers/class.ilFormATestSetsGUI.php
+++ b/classes/controllers/class.ilFormATestSetsGUI.php
@@ -68,7 +68,7 @@ class ilFormATestSetsGUI extends ilXTSFControllerTableGUI
 		{
 			ilUtil::sendInfo($this->plugin->txt("no_access_to_sets"), true);
 		}
-		elseif(count($data) == 0)
+		elseif(is_array($data) && count($data) == 0)
 		{
 			ilUtil::sendInfo($this->plugin->txt("no_sets_existing"), true);
 		}
@@ -165,12 +165,14 @@ class ilFormATestSetsGUI extends ilXTSFControllerTableGUI
 				return $a["sorting"] - $b["sorting"];
 			});
 
-		for($i = 0; $i < count($data); $i++)
+		if(is_array($data))
 		{
-			$data[$i]["sorting"] = ($i + 1)* 10;
-			$this->controller->object->getSetList()->update($data[$i]);
+			for($i = 0; $i < count($data); $i++)
+			{
+				$data[$i]["sorting"] = ($i + 1) * 10;
+				$this->controller->object->getSetList()->update($data[$i]);
+			}
 		}
-
 		return $data;
 	}
 
diff --git a/classes/models/class.ilFormATestParticipantsList.php b/classes/models/class.ilFormATestParticipantsList.php
index 58727a18fece9de9804ba4a9781e13076ba858b7..9a1eb809194a06ce8eab76c2bb4e1871055cfc4d 100644
--- a/classes/models/class.ilFormATestParticipantsList.php
+++ b/classes/models/class.ilFormATestParticipantsList.php
@@ -48,6 +48,7 @@ class ilFormATestParticipantsList extends ilXTSFModelList
 	 */
 	public function hasParticipants()
 	{
+		if(is_array($this->getData()))
 		return count($this->getData()) > 0;
 	}
 
diff --git a/classes/models/class.ilFormATestQuestionSetPoolSetList.php b/classes/models/class.ilFormATestQuestionSetPoolSetList.php
index 54994e6e5ce36543cace2b63cb1105366fb37524..7e1af74794989fd02af3b3c8d08d5e23f3746b26 100644
--- a/classes/models/class.ilFormATestQuestionSetPoolSetList.php
+++ b/classes/models/class.ilFormATestQuestionSetPoolSetList.php
@@ -22,7 +22,7 @@ class ilFormATestQuestionSetPoolSetList extends ilXTSFModelList
 
 		$available_pools = array_keys(ilObjQuestionSetPool::getAvailableQuestionSetPools());
 
-		if(count($available_pools) == 0)
+		if(is_array($available_pools) && count($available_pools) == 0)
 		{
 			return null;
 		}
diff --git a/classes/models/class.ilFormATestSession.php b/classes/models/class.ilFormATestSession.php
index 02778f1473612837800cd8e0a469d10594361153..afdbd9f82fae73d43383de61a9bdb06e3ffbfadc 100644
--- a/classes/models/class.ilFormATestSession.php
+++ b/classes/models/class.ilFormATestSession.php
@@ -139,7 +139,12 @@ class ilFormATestSession
 	 */
 	public function hasNextSet()
 	{
-		return array_search($this->current_position, $this->sets) < count($this->sets) - 1;
+		if(is_array($this->sets))
+		{
+			$set_count = count($this->sets);
+		}
+		
+		return array_search($this->current_position, $this->sets) < $set_count - 1;
 	}
 
 	/**
@@ -558,7 +563,7 @@ class ilFormATestSession
 	public function stepHasSolution($node)
 	{
 		$result = $node->getQuestion()->getUserQuestionResult($this->active_id, $this->pass);
-
+if(is_array($result->getSolutions()))
 		return count($result->getSolutions()) > 0;
 	}
 
@@ -569,6 +574,7 @@ class ilFormATestSession
 	 */
 	public function hasStepsToDelete($node)
 	{
+		if(is_array($this->getStepsToDelete($node)))
 		return count($this->getStepsToDelete($node)) > 0;
 	}
 
diff --git a/classes/tables/class.ilFormATestResultsTableGUI.php b/classes/tables/class.ilFormATestResultsTableGUI.php
index 3471c5d4936b95bdc264fd0eb6789aea1d96035c..cb3a99c460d0975aa865899e2ec9e127f5f3c409 100644
--- a/classes/tables/class.ilFormATestResultsTableGUI.php
+++ b/classes/tables/class.ilFormATestResultsTableGUI.php
@@ -80,6 +80,7 @@ class ilFormATestResultsTableGUI extends ilXTSFTableGUI
 	{
 		parent::prepareData($data);
 
+		if(is_array($data))
 		$data[\count($data)-1]["scored"] = "&otimes;";
 	}
 
diff --git a/classes/utils/abstract.ilFormATestUtil.php b/classes/utils/abstract.ilFormATestUtil.php
index c2f2be346595b065290d777f3df2b2c1c8ffe5fe..76df49b1fbe5d0b42b5c78816afccf8510317274 100644
--- a/classes/utils/abstract.ilFormATestUtil.php
+++ b/classes/utils/abstract.ilFormATestUtil.php
@@ -52,16 +52,19 @@ abstract class ilFormATestUtil {
 
 	protected static function hasInfos()
 	{
+		if(is_array($_SESSION[self::$INFO_KEY]))
 		return count($_SESSION[self::$INFO_KEY]) > 0;
 	}
 
 	protected static function hasSuccess()
 	{
+		if(is_array($_SESSION[self::$SUCCESS_KEY]))
 		return count($_SESSION[self::$SUCCESS_KEY]) > 0;
 	}
 
 	protected static function hasErorrs()
 	{
+		if(is_array($_SESSION[self::$ERROR_KEY]))
 		return count($_SESSION[self::$ERROR_KEY]) > 0;
 	}
 
@@ -72,7 +75,7 @@ abstract class ilFormATestUtil {
 
 	protected static function prepare($key)
 	{
-		if(count($_SESSION[$key]) == 1)
+		if(is_array($_SESSION[$key]) && count($_SESSION[$key]) == 1)
 		{
 			return current($_SESSION[$key]);
 		}
diff --git a/classes/utils/class.ilFormATestAccordionGUI.php b/classes/utils/class.ilFormATestAccordionGUI.php
index 2ca56a71a6f1e3c84639a7a0425b9542988f7e0e..26e03f5e255a8fc591684e541a6c64e6db145eb2 100644
--- a/classes/utils/class.ilFormATestAccordionGUI.php
+++ b/classes/utils/class.ilFormATestAccordionGUI.php
@@ -264,9 +264,9 @@ class ilFormATestAccordionGUI
 		$this->items[] = array("header" => $a_header,
 							   "content" => $a_content);
 
-		if($a_force_open)
+		if($a_force_open && is_array($this->items))
 		{
-			$this->force_open = sizeof($this->items);
+			$this->force_open = count($this->items);
 		}
 	}
 
diff --git a/classes/utils/class.ilFormATestInfoScreenGUI.php b/classes/utils/class.ilFormATestInfoScreenGUI.php
index 98ce17c88e4b80dc9f1f4eec4216b13e93bcbe2e..6ed5f888a30911c7a176c465c16097e07fab5b2b 100644
--- a/classes/utils/class.ilFormATestInfoScreenGUI.php
+++ b/classes/utils/class.ilFormATestInfoScreenGUI.php
@@ -61,7 +61,7 @@ class ilFormATestInfoScreenGUI extends ilInfoScreenGUI {
 			}
 		}
 		// add top buttons
-		if (count($this->top_buttons) > 0)
+		if (is_array($this->top_buttons) && count($this->top_buttons) > 0)
 		{
 			$tpl->addBlockfile("TOP_BUTTONS", "top_buttons", "tpl.buttons.html");
 
@@ -81,7 +81,7 @@ class ilFormATestInfoScreenGUI extends ilInfoScreenGUI {
 		}
 
 		// add top formbuttons
-		if ((count($this->top_formbuttons) > 0) && (strlen($this->form_action) > 0))
+		if ((is_array($this->top_formbuttons) && count($this->top_formbuttons) > 0) && (strlen($this->form_action) > 0))
 		{
 			$tpl->addBlockfile("TOP_FORMBUTTONS", "top_submitbuttons", "tpl.submitbuttons.html", "Services/InfoScreen");
 
@@ -111,7 +111,7 @@ class ilFormATestInfoScreenGUI extends ilInfoScreenGUI {
 			}
 		}
 
-		if (count($this->hiddenelements))
+		if (is_array($this->hiddenelements) && count($this->hiddenelements))
 		{
 			foreach ($this->hiddenelements as $hidden)
 			{
diff --git a/plugin.php b/plugin.php
index 4b604735f080f20478a4ea7bc036756303612b5c..4f3d6fa07e0100a16fb4e6ffc4972e2c254aed25 100644
--- a/plugin.php
+++ b/plugin.php
@@ -3,12 +3,12 @@
 $id = 'xtsf';
 
 // code version; must be changed for all code changes
-$version = '5.0.2';
+$version = '6.0.0';
 
 // ilias min and max version; must always reflect the versions that should
 // run with the plugin
 $ilias_min_version = '5.3.0';
-$ilias_max_version = '5.3.999';
+$ilias_max_version = '5.4.999';
 
 // optional, but useful: Add one or more responsible persons and a contact email
 $responsible = 'Thomas Joussen / Michael Jansen';