I've been having a similar problem with gdm. twm starts up fine (that's what I'm in now), but gdm stops after it displays it's flash screen, but before it shows any of the icons along the bottom edge. Here's my .xsession-error FWIW:
/etc/X11/gdm/PreSession//Default: Registering your session with wtmp and utmp
/etc/X11/gdm/PreSession//Default: running: sessreg -a -w /var/log/wtmp -u /var/run/utmp -x "/var/lib/gdm/:0.Xservers" -h "" -l :0 lsiden
I looked in /var/lib/gdm and found :0.log. It's contents are:
XFree86 Version 4.3.0
Release Date: 27 February 2003
X Protocol Version 11, Revision 0, Release 6.6
Build Operating System: Linux 2.4.19-gentoo-r9 i686 [ELF]
Build Date: 06 May 2003
Before reporting problems, check
http://www.XFree86.Org/
to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/XFree86.0.log", Time: Tue Jun 17 15:48:20 2003
(==) Using config file: "/etc/X11/XF86Config"
AUDIT: Tue Jun 17 15:50:46 2003: 3104 X: client 5 rejected from local host
AUDIT: Tue Jun 17 15:50:46 2003: 3104 X: client 5 rejected from local host
I'm not sure I understand what the last line means: "client 5 rejected ...". What is "client 5"?
The recent changes on my system include emerging xscreensaver, which was a prime suspect, so I unmerged it. Another suspect was samba, so I disabled it. I also tried disabling cups, since I had modified cupsd.conf, but none of the above helped. I'm quite stumped.