Fatal error: Uncaught Error: Undefined constant "PKP\form\validation\PKP_STRICT_MODE" in C:\xampp\htdocs\ojs\lib\pkp\classes\form\validation\FormValidator.php:189 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ojs\lib\pkp\classes\form\validation\FormValidator.php on line 189