Can't log non root users into X
When I try to log a non root user in using kdm, the screen goes blank, then returns to kdm. Any user can log in using a vurtual terminal. Using the startx command from a vurtual terminal produces what looks like normal messages but conntaning "user is not allowed to use X windows".
I've googled the problem, and it seems to be related to user permisions, however the all the forums I found it on are ether left unresolved, or fixed by a resedent Alfa Geek.
What permisions does a user need to run X?