Fatal error: Uncaught Error: Class "ilXmlWriter" not found in /var/www/html/ilias/components/ILIAS/Exercise/classes/class.ilExerciseXMLWriter.php:27 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Exercise/classes/class.ilExerciseXMLWriter.php on line 27