Fatal error: Uncaught Error: Class "ilContainerReferenceGUI" not found in /var/www/html/ilias/components/ILIAS/CourseReference/classes/class.ilObjCourseReferenceGUI.php:26 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/CourseReference/classes/class.ilObjCourseReferenceGUI.php on line 26