Remote X display from a minimal install - testing gui rpm package

[David Timms <dtimms@xxxxxxxxxxxx>]

I have installed a fairly minimal Fedora 7 machine ~150 rpms. I am 
trying to test a gui package I am working on. So, I have yum installed 
the test package on that machine.
Following: http://www.linuxhowtos.org/Tips%20and%20Tricks/export_x.htm
I login as testuser. I try to export the display:
export DISPLAY=192.168.0.201:0

Then on a separate machine with X/gnome/testuser logged in etc, I, for 
now, disable the firewall, and set xhost +192.168.0.99

Then back on the minimal install machine I run xclock {or my app}.

The result is the terminal session pauses for about 5-6 seconds, and 
then: Error: Can't open display: 192.168.32.101:0.0
{with the firewall up the error is immediate}

I think I might be needing some non-default X package {client?} on the 
minimal install, but what would that be - or am I doing something else 
wrong ?

Thanks, DaveT.