I didn't *really* solve this but I did find a way to avoid the "greeter" 
screen that was totally bugging out.  The /etc/gdm/custom.conf file was 
essentially empty so I added two "AutoMaticLogin" lines immediately after 
"[daemon]":

[daemon]
AutomaticLoginEnable=true
AutomaticLogin=user

Where "user" was my username.  This makes it so that I am logged in 
automatically at boot up and the greeter is skipped.  So it doesn't really 
fix the problem but it avoids it well enough for me (if someone breaks 
into my office and knows what he's doing, I'm screwed no matter what!).

It seemed to be a pretty long and painful upgrade because of this one 
major problem but I did learn a few things and I'm sure I'll do it again 
in six months.

Mike


On Mon, 30 Nov 2009, Mike Miller wrote:

> After about 10 hours of working on this and basically getting nowhere, 
> I'm prepared to take more radical steps.  I still can't get to Gnome 
> desktop, but I don't need to use it.  In fact, I usually do not use it. 
> I usually use icewm in vnc.
>
> What I need is a way to get to my VNC session on the local machine 
> without running gdm.  Is that hard to do?
>
> By the way, I find that these log files...
>
> /var/log/gdm/:0-greeter.log
>
> ...grow at a rate of about 100 MB every hour or so when I'm trying to get gdm 
> working.  Almost all of the output consists of repetitions of sections that 
> look like this but with the process number increasing:
>
> ** (process:1888): DEBUG: Greeter session pid=1888 display=:0.0 
> xauthority=/var/run/gdm/auth-for-gdm-VjBW5d/database
> gdm[1893]: ******************* START **********************************
> gdm[1893]: [Thread debugging using libthread_db enabled]
> [snip]
> gdm[1893]: No symbol table info available.
> gdm[1893]: A debugging session is active.
> gdm[1893]:
> gdm[1893]:      Inferior 1 [process 1888] will be detached.
> gdm[1893]:
> gdm[1893]: Quit anyway? (y or n) [answered Y; input not from terminal]
>
> Where "[snip]" represents about 132 lines of information - I didn't want to 
> clutter the list, but I'm happy to share it.  The log file contains many 
> lines that have been chopped off on the right side, for example, sometimes 
> instead of "Quit anyway?" it says "t anyway?"
>
> Apparently it is trying many times to run the greeter (several times per 
> second, I'd say) and it is failing.
>
> Mike