Don't know what else I could update... I have the latest BIOS, Via 4-in-1 drivers, Audigy Drivers, Windows Updates, and the second to latest ATI Catalyst drivers (3.8). I tried 3.9, but I kept getting bluescreens, and I saw a blurb on the Technical FAQ that recommended the 3.8's for this very reason. I've also tried tweaking BIOS settings, setting "fail-safe" defaults, disabling all unnecessary services with msconfig, etc., etc., etc.
I have already put waaay too much time and money into trying to get this game to work. At this point, I really feel like I've done everything I can do. I think the game is great, but it is simply not stable on my system. Fortunately, it runs flawlessly on my laptop, so I've still been able to play the game at lower fidelity. I don't have this problem with other 3d games, so I think the fault is in either Uru or the combination of it and my video driver. I hope that a future Uru or Catalyst driver update will correct this, and that it comes out before I get my Live invitation. I really like the game, and I want to play it on my gaming rig.