Did you install the mobo's AGP driver?
Also, I use the unified nvidia drivers for all my nvidia cards including the 2 Gainward GF3 cards I have (64 and 128 MB) and have no problems.
I did a search on google, came up with alot of results indicating:
The driver for the display device got stuck in an infinite loop. This usually indicates a problem with the device itself or with the device driver programming the hardware incorrectly. Please check with your display device vendor for any driver updates.
http://www.xe4500-crash.com/problem.php
WB