Fatal error: Uncaught Error: Class "ilContainerReferenceXmlParser" not found in /var/www/html/ilias/components/ILIAS/CourseReference/classes/class.ilCourseReferenceXmlParser.php:35 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/CourseReference/classes/class.ilCourseReferenceXmlParser.php on line 35