Everybody who's having this problem should check the Paranoia tab in TweakUI. Make sure that you UNcheck the "Clear Last User at logon" item, then apply that. Now that autologon is allowed to remember who the last user was, it will be able to supply the password and log you on.
There are other possibilities, but this is the one that seems to bite the most people in the butt.
Regards,
Jim