Fatal error: Uncaught Error: Undefined constant "PKP\form\PKP_STRICT_MODE" in C:\xampp\htdocs\ojs\lib\pkp\classes\form\FormBuilderVocabulary.php:987 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ojs\lib\pkp\classes\form\FormBuilderVocabulary.php on line 987