I've upgraded to 2.5.1 and just noticed that my dashboard isn't working. all my others are, hence why I didn't notice. I get an error:
Fatal error: Call to undefined function: register_sidebar() in /home/-/-/-/wp-admin/includes/dashboard.php on line 13
So, is it a widget that was installed in 2.5.1? I don't have any personal widgets ( i think) unless plugins are messing this up.
Any help would be appreciated.