Oblivion crashes

when i try to run Oblivion it works at first, but around the time the king comes into the cell it turns off and gives me an error report that says this: C:\DOCUME~1\EVL\LOCALS~1\Temp\e724_appcompat.txt. the e724 part changes. what can i do

Computer:
Gateway
windows XP
AMD Athlon 64 X2 Dual core processor 3800+
2.00 GHz, 1 1/2 GB of ram left (not counting what the computer hard drive will store)
NVIDIA GeForce 6800 running 512 memory


I have all the requirements and then some and it still gives me crap.
any help would be appreciated, thanks