Fatal error: Uncaught Error: Class "ilContainerBaseXmlParser" not found in /var/www/html/ilias/components/ILIAS/ContainerReference/classes/class.ilContainerReferenceXmlParser.php:23 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/ContainerReference/classes/class.ilContainerReferenceXmlParser.php on line 23