Warning: Undefined variable $OUTPUT in C:\xampp\htdocs\laberit01\html\moodle\theme\lambda\layout\popup.php on line 24

Fatal error: Uncaught Error: Call to a member function doctype() on null in C:\xampp\htdocs\laberit01\html\moodle\theme\lambda\layout\popup.php:24 Stack trace: #0 {main} thrown in C:\xampp\htdocs\laberit01\html\moodle\theme\lambda\layout\popup.php on line 24