gdm: failed to start the display server

[Lutz Lennardt <lutz.lennardt@onlinehome.de>]

I can login with gdm (Version: 2.2.5.5-2) but when logging off from the 
x-server gdm fails to start again.

"failed to start the display server several times in a short time 
period; disabling display :0"

Does anybody know how to fix this?

-- 
Lutz