Fatal error: Uncaught Error: Class "PHPExcel_Writer_Abstract" not found in D:\HTTP\htdocs\gincludes\PHPExcel-develop\Classes\PHPExcel\Writer\OpenDocument.php:38 Stack trace: #0 {main} thrown in D:\HTTP\htdocs\gincludes\PHPExcel-develop\Classes\PHPExcel\Writer\OpenDocument.php on line 38