X sessions die when using KDM

[Jason Majors <jason@whizzird.net>]

When I use KDM to start X, after logging in it goes right back to the kdm
login screen.
I can login from the console and run X with startx without a problem though.
Here are the lines from applicable logs:

auth.log
Oct 19 12:12:21 scd714 PAM_unix[692]: (kde) session opened for user jmajors by (uid=0)
Oct 19 12:12:21 scd714 PAM_unix[692]: (kde) session closed for user jmajors

daemon.log
Oct 19 12:08:10 scd714 kdm[262]: Server for display :0 terminated unexpectedly
Oct 19 12:08:10 scd714 kdm[262]: Display :0 is being disabled (restarting too fast)

Does anybody know what the problem is here?

Thanks,
Jason