I solved the problem, by editing the tellck.php file. For anyone else who might need the solution.
META HTTP-EQUIV=REFRESH CONTENT="6;URL=http://www.diabetic.pub/forum//index.php?
Just remove the "?" at the end of the code. I don't know how it got inserted there in the first place. It led to the user getting logged out of the forum, though being redirected to the index page.