Fatal error: Uncaught Error: Class 'PHPExcel_Writer_Excel5_BIFFwriter' not found in D:\xampp\htdocs\GM\Classes\PHPExcel\Writer\Excel5\Workbook.php:63 Stack trace: #0 {main} thrown in D:\xampp\htdocs\GM\Classes\PHPExcel\Writer\Excel5\Workbook.php on line 63