gdm won't authenticate

[Tim Lewis <talewis worldnet att net>]

Hello All,
I tried getting GDM running again last night, taking into account the
notes offered by other users on this list.  First, I found gdm.conf
non-existent, so I copied the rpmsave  file to it.  Then there were
permissions/ownership issues to resolve in /usr/var/gdm and
/usr/etc/gdm; fixed them.  Then I finally got a login box, but it kept
replying 'invalid user and password'.  I checked /var/log/messages, and
found:

Mar  4 21:05:32 localhost gdm[20617]: gdm_auth_secure_display: Could not
unlink /usr/var/gdm/:0.xauth file: No such file or directory
Mar  4 21:05:37 localhost gdm[20621]: Couldn't authenticate root
Mar  4 21:05:44 localhost last message repeated 2 times

I tried creating a dummy file there, but to no avail.  I also tried
logging in as a normal user with no success.  XDM functions correctly. 
Any suggestions??
Thanks for the help,
Tim