I got a similar problem and I guess it's because of Xfire and the memory in the cod processus.
In my computer (windows7 64), when xfire is launched and that the cod map is changing, i noticed the memory is not released in the cod processus. So the global memory of the processus increase on each map without decrease... And when it's too high (1,5Gb or 2Gb) my game crash with iw3 error, that's happen after one or two rotations of maps...
So when i'm playing, i shutdown xfire now.
Do you use Xfire ingame Angel?
Maybe it's not the same problem than me but if it is and someone has a solution, please help us ^^
And sry if my english is not very understandable
Edit : How you fixed your pb angel?