I've got the same problem as the initial poster with black screen when logging out but with kde 4.2.4. I've checked the kdmrc file in usr/kde /4.2/share/config/kdm - TerminateServer=true is on. so this fix doesn't work on my machine.
Any thoughts of how to fixing this? anyone else got this problem?
Compiz, KDE, Gnome, Fluxbox, etc...