There should be nothing wrong with the functions.php file, the problem will be in the page that has called it.
Have you followed the steps in the troubleshooting guide?
https://vborg.vbsupport.ru/showpost....79&postcount=2
Including step 5 with the test code.
If you still have problems after this, please post the first few lines of the page you are trying to use this hack on.