Hi there !
I use Debian Squeeze (and testing) with MintUpdate (and some others LMDE tweaks). I don't use sudo and i've found a kind of bug with MUpdate.
I can get trought it via the gnome control center (or the administration menu), it will ask my root password and work as intended. However, if i try to access it via the systray icon, it will ask a password and it won't work, no matter if i enter my root or user password. I think it has to do with sudo.
Is this a known behavior ?