How to remove this error from my forum

[baby41]

Everytime I try to open a forum gives me this error:

Fatal error: Call to a member function on a non-object in /home/xxxxxxx/public_html/forum/includes/functions_forumdisplay.php on line 170

[Analogpoint]

Things to try:

1. Disable all modifications
2. Re-upload all original vBulletin *.php files

[baby41]

Thanks for the tip,I have re-upload file "functions_forumdisplay.php" and everything is sorted now,thanks.