I’m having the same problems and I am using 0.5.1.
Thanks Mo, modifying the database seemed to do the trick!
I got the same thing. This is the error message I get when I installed new version:
Fatal error: Cannot use object of type WP_Error as array in /home/lctvonet/public_html/myduhawk/wp-content/plugins/edit-flow/php/usergroups.php on line 333
