Forum Crash after 3.0

[bsavi]

After the 3.0 update the forum has crashed completely and now when you go to http://www.modern-muscle.com you get this error message

Fatal error: Cannot redeclare is_rtl() (previously declared in /home/mmuscle/public_html/wp-includes/locale.php:347) in /home/mmuscle/public_html/wp-includes/locale.php on line 349

I have no idea what happened, I have no access to the control panel!

[Anonymous User]

and which forum would this be?

either way you need to disable all plugins (via FTP or phpmyadmin)

Then renable one by one until you find the culprit.