Login in to my user account , I just get “could not open kstartupconfig check your configuration” and a blank desktop.
Just an idea, never had this problem…
You could try:
ALT-F2, start konqueror, rename ~/.kde/share/config to something else and restart KDE. A new standard desktop / config directory should be created.
If it doesn’t work you can revert the changes by renaming back the config directory.