Fatal error after upgrade

I performed an auto upgrade to WP 3.0, and it said everything was fine, I clicked dashboard, and got this:

Fatal error: Cannot redeclare is_rtl() (previously declared in /home2/shellbac/public_html/wp-includes/locale.php:347) in /home2/shellbac/public_html/wp-includes/locale.php on line 349

Now I can’t even access my site or log in…Any help would be appreciated.