3.5.13 cannot login via KDE4 or failsave

Hello I am running trinity 3.5.13 on Kubuntu 10.04 for a while without much trouble. I just wanted to login using KDE4 or failsave, the login manager accepts my password seems to start one of these windows manager but then returns to the login screen. What could be the problem? Since I cannot use the trinity control Center for the User Administration (outstanding trinity bug) I cannot try to do it as a different user. Uwe Brauer