Hi all!
Just in case somebody runs into the same issue:
When you configure TDE so that - it shuts down the computer when you log out - should not show the logout dialog chances are ksmserver segfaults on logout instead of shutting the computer down. If it happens to you check that in .trinity/share/config/ksmserverrc these two enries are set to "false":
[Logout] doFancyLogout=false showLogoutStatusDlg=false
Nik