That KX133 might be problematic under XP. I'd snag a copy of the 4.41 VIA 4-in-1 drivers and give those a shot. You might also want to force the card to use AGP 2x or 1x in your BIOS and through software (I think RivaTuner might have this option). You could also try the "Large page minimum" registry hack that we had to use for Windows 2000 so our games wouldn't lock up. That reg fix should be available for download at www.amd.com
If I think of anything else off the top of my head, I'll be sure to post it.