Running SuSE 9.1.
I have the same problem as hedgehog. What I did was switch user to start a 2nd session as root (in order to edit a config file). Out of curiosity (substitute stupidity if you like) I hit the adminstrator button on the log in window that appeared. This took me straight to Yast as root. Now I can't log in as root anymore, without going straight to YaST an being unable to get to kde as root. I have tried logging in at boot as root, swtiching use to root, and logging in from terminal. None of them work.