Fatal error: Uncaught Error: Undefined constant "PHPEXCEL_ROOT" in D:\HTTP\htdocs\gincludes\PHPExcel-develop\Classes\PHPExcel\Shared\trend\linearBestFitClass.php:29 Stack trace: #0 {main} thrown in D:\HTTP\htdocs\gincludes\PHPExcel-develop\Classes\PHPExcel\Shared\trend\linearBestFitClass.php on line 29