Here is the error:
Warning: call_user_func() expects parameter 1 to be a valid callback, no array or string given in /home/bloodyca/public_html/wp-includes/functions.php on line 2117
This site has lost its Dashboard navigation completely as well as some of the center content. The word Dashboard has moved into the center content area, no longer over the nav menu. This keeps me from testing the 'conventional way', however here is what I have done to rectify through cpanel.
Tested using IE and Firefox. Disabled all plugins= no change; changed theme = no change; replaced all WP v3.81 core files except content, with fresh download & extract on server= no change; checked user role permissions in DB vs a fresh bare bones install on another server= nothing; compared DB versions = identical; Searched, read and tried first 10 pages of results from SE (most results were antiquated versions) but were read & tested = no change; checked first page results on WP forum T&H , seems lots of people have a problem but no solutions, yet.
btw.. in the search results it would be nice if we could filter by date or version