Can't start more than one gnome-session as the same user?

[Clint Olsen]

I'm trying to do some diagnostic work on my machine, so I'm actually
physically logged in, and I also have Gnome setup to run when I start VNC,
however the two don't play well simultaneously.  I get the message:

gnome-session: you're already running a session manager

I've never heard of such a busted system where you can only run one copy of
a window system at one time on a machine.  Man, this nightmare sounds like
something I'd find in Microsoft Windows.

I searched and found a lot of old hits of this error.  The solutions are
not very compelling.  Unsetting SESSION_MANAGER before launching vncserver
only cascades errors down into the various client programs like the desktop
etc.

Any suggestions would be appreciated.

Thanks,

-Clint