Thanks for your replies.
it seems to be a problem of mine though. happened again while playing a newspaper mission.
I looked in my system logs, and it seems to a be a kernel error (blue screen stuff, only I don't get the blue screen), along with "invalid parameters" sent to my video card.
I have:
Asus P5BE motherboard (IIRC)
Intel DualCore Duo 2.13 Ghz
2Gb RAM
Radeon X1950 Pro graphic card 256mb DDR3
I'm running CoH in 1280x1024, and it started getting freaky only today. Pretty strange.
I'll defrag, update drivers and see what happens.
Thanks for your help!!