Exception thrown `autoupdate_admin_controller` not defined for ExtensibleObject

Any attempt to access the dashboard or use any of the other top menu items results in a white page reading:

Exception thrown

autoupdate_admin_controller not defined for ExtensibleObject

I have not seen this error listed on this forum. In fact, Googling this error does returns zero results.

I do not know where to even begin troubleshooting this since the error blocks access to WordPress on my site. The site itself seems to be working, although it is responding very slowly. Posts, pages ,and galleries are showing up as they should.

I am using the Photocrati theme and NextGen Galleries. One of these may be the cause.