HELP PLEASE.

PROBLEM: (Mythbuntu 10.10): at various points (see details below) I'm given a "login as" screen; I login as main user with password, then, after a moment, the "login as" screen appears again.

This problem appears similar to those reported in

http://ubuntuforums.org/showthread.php?t=1681908

http://ubuntuforums.org/showthread.php?t=1681985

but with some differences.

HISTORY AND DETAILS: The installation was working fairly well for awhile. Then I tried out a few desktop themes; one of them put me into the loop described above, making it impossible to reach the xfce desktop or anything else except the recovery console. So I did a:

FRESH MYTHBUNTU 10.10 INSTALL (and Mythtv backend setup). After which it would boot into the Mythtv frontend but I could exit and reach the desktop fine. Then, during the Mythtv frontend setup, I thought I'd change the frontend theme (stupid, perhaps, but I didn't at the time suspect that the previous xfce theme change had anything to do with my problem). After that, the computer would still boot up into the frontend, and I could exit to the desktop with no problem, but if I stayed in (or went back to) the frontend and chose the "Watch TV" option... I got the repeating "login as" screen again.

So, thinking it might have to do with changing the frontend theme, I did yet another fresh install, Mythtv backend setup, and Mythtv frontend setup WITHOUT changing the theme. No luck: I still get the repeating "login as" screen.

Help. Help.