Fatal error: Uncaught Error: Undefined constant "PKP\linkAction\request\PKP_STRICT_MODE" in C:\xampp\htdocs\ojs\lib\pkp\classes\linkAction\request\LinkActionRequest.php:59 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ojs\lib\pkp\classes\linkAction\request\LinkActionRequest.php on line 59