MyBB Community Forums

I get this when I want to acces any category/forum/subforum:

Fatal error: Call to undefined function fetch_unread_count() in /home/accounts_f/fortepiany/public_html/forumdisplay.php on line 1159

I tried:
chmoding
reuploading files
clearing cookies and cache

Site:
fortepiany.boo.pl

Reupload functions.php

Solved. Reuploading fucntions.php didn't work so I've reuploaded all functions_*.php and it worked.

Thank You for advice.