I am having something very similar with new registrations.
No amount of backups or manipulation can cure it.1062 Duplicate entry '' for key 2
in:
[insert into phpbb_users (user_id, username, user_password, user_email, user_regdate) values ('55', 'name', '827ccb0eea8a706c4c34a16891f84e7b', '[email protected]', '1227828529')]
(ZC 1.3.8a & phpbb3)



