Nav Menu disabled in 3.1.2 – nav-menus.php

I am experiencing a problem with my ‘Menus’ screen (admin/nav-menus.php) where my navigation menus are disabled. I have all my plugins deactivated. I have tried to access this page using twentyten and my child theme of twentyten. Currently the only thing on the screen is the ‘Theme Locations’ menu and ‘Custom Links’ menu, but those are ‘grayed’ out. The normal main area where you would drag and drop the links is missing. Inspecting the code reveals that the ‘Theme Locations’ and ‘Custom Link’ elements all have ‘disabled’ associated with them.

Is there a script or database setting that is triggering these to become disabled?