I'm having an additional problem, which may be related. I cannot get my changes to the groups to take effect. In fact, if I make ANY change to either the groups a user is part of, or the group read/write priviledges for individual boards, ALL the options are erased - the user is removed from all groups, and noone at all is allowed read/write privileges for the board. (this was happening before I issued the DELETE FROM command)
I did the DELETE FROM fix detailed in this thread, and it removed all the groups except "user" (from the "rename groups" screen and "assign user to group" screen). The read/write privileges screens, however, keep showing the admin/moderator/users/guests groups. I'm assuming that these are system-level groups that you can't mess with (which I like).
Mine is a fresh install from the 5.1.6 files - I uploaded to a different directory from where I had my demo files (although the database is the same one I used in the demo).
Thanks,
John