Fatal error: Uncaught Error: Class "ilContainerReferenceXmlParser" not found in /var/www/html/ilias/components/ILIAS/CategoryReference/Export/class.ilCategoryReferenceXmlParser.php:26 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/CategoryReference/Export/class.ilCategoryReferenceXmlParser.php on line 26