I've just migrated my wordpress site from one host to another, and I'm getting this error for the plugin. When I go to the Menu Editor page from the Settings dropdown, I see the cut, copy paste, etc. Buttons and "Save Changes", "Undo Changes" and "Load Default Menu" buttons, but nothing else (none of the menu items are there.)
I've tried deleting the database data and plugin and reinstalling - both from a file on my computer as well as searching for the plugin within the admin.
Can't figure this one out, any ideas would be appreciated!