This started out as a question. But I fixed it (after 2 days of struggle). So I thought I'd share my solution to this particular problem. It THINK it is just Fedora (FC5) related, but that's probably wrong. Disclaimer: This is my first posting.

The problem was that I couldn't sign into my account. I got the following message...which is a very common message in an otherwise complex process...

Your session only lasted less than 10 seconds. etc. etc.

~/.xsession-errors dump is......

/etc/gdm/PresSession/Default: Registering your session with wtmp and utmp
/etc/gdm/PresSession/Default: running: /usr/bin/sessreg -a -w /var/log/wtmp -u /var/run/utmp -x "/var/gdm/:21.Xservers" -h "" -l ":21" "thisUser"
xset: bad font path element (#584), possible causes are:
Directory does not exist or has wrong permissions
Directory missing fonts.dir
Incorrect font server address or syntax
startkde: Starting up...
startkde: Shutting down...
klauncher: Exiting on signal 1
startkde: Running shutdown scripts...
startkde: Done.

directory.fonts exists and has correct permissions.
I didn't know how to get the font server address as described.
Funny thing is that my other accounts didn't even have a .fonts directory or a fonts.conf file. And they work fine. ???

So after doing a binary search/replacement of each file, I discovered the bad file was .rh-fontconfig. I don't know what that does. But replacing that file with a file from another account/old backup or whatever, it was magic. I guess some font description in that binary file got broke somehow. I had shut down the computer via another account when that account was active. It was running a WINE simulation of a not-so-reliable windows text program with lots of funny fonts. That's my best guess about what was going wrong.

Er...what is .rh-fontconfig? Could I have just deleted it? It looks like something that could easily have been regenerated in the normal use of things.