After finishing an FC4->FC5 upgrade, I'm finding some problems with gdm. After selecting GNOME as my session type and logging in normally, gnome-session fails to start and the window manager is twm rather than metacity. I believe the issue is with gdm because using startx brings up gnome-session normally. Also, this doesn't appear to be an issue of old configuration files in the home directory. I created a new user account to verify this and logging in as this new user still reproduced the symptoms above. Any ideas on what might be the problem?