Fatal error: Uncaught Error: Class 'MantisPlugin' not found in C:\inetpub\wwwroot\mantis\plugins\XmlImportExport\XmlImportExport.php:29 Stack trace: #0 {main} thrown in C:\inetpub\wwwroot\mantis\plugins\XmlImportExport\XmlImportExport.php on line 29