Shouldn't take long to fix this problem. I use WPMU + Buddypress. When someone logs in (in the sidebar), the log in box is replaced by the account name and an avatar. The problem is, something seem to be wrong with the code. Because sometimes when someone tries to log in, they get logged in as a different user. For example: I log in as michael It shows the name and avatar of scott. Also, you can't log in on sub-pages. Probably just a simple error in a row in the wp-sidebar.php