have you read the troubleshooting 3.3 master list: http://wordpress.org/support/topic/troubleshooting-wordpress-33-master-list
try:
– resetting the plugins folder by using FTP or whatever file management application your host provides. Sometimes, an apparently inactive plugin can still cause problems.
– switching to the default theme by renaming your current theme’s folder in wp-content/themes using FTP or whatever file management application your host provides.
– re-uploading all files & folders – except the wp-content folder from a fresh download of WordPress. by using FTP or whatever file management application your host provides. (manual upgrade)
I had the same issue. Resetting the plugins folder worked like a charm. Thanks keesiemeijer
Thank You soooo much for this post!
Had the exact same error message: Fatal error: Call to undefined function is_rtl() in /home/public_html/wp-includes/general-template.php on line 2102.
I reset the plugins folder and found it was my ‘pop up domination’ plugin that was causing the error.
Deleted the file and will now ask for an updated version of the plugin.
Thanks howuk! Deleted the popup domination folder and all now works great!!!
El Popup Domination es el problema.
