gnome-session child process not killed by vncserver

[Mike Miller]

On Red Hat Linux running Xvnc version 4.0b4, starting gnome-session as 
follows...

#!/bin/sh

xrdb $HOME/.Xdefaults
xsetroot -solid grey
vncconfig -nowin &
exec autocutsel &
/usr/bin/xterm -geometry 80x51+78+25 -ls -T "`whoami`@`hostname`" &
exec gnome-session &

...we had a problem where the gnome-session was somehow corrupted and 
would not start properly until we deleted both ~/.gconf and ~/.gconfd. 
After each attempt we killed the Xvnc session using vncserver -kill :n. 
One big problem:  One of the gnome-session processes was not killed along 
with Xvnc and it continued to run.  It ate up all the memory and swap on 
the system in about 2.5 hours.  Then I discovered it and killed it.  In 
the meantime, I had started another Xvnc with the same display number.

Tell me if you know what might cause this kind of thing to happen so that 
I can avoid it in the future.

Mike