I have seen that message a few times.
I had alot of problem with the game freezing at more or less random, I have tried several of the sugested fixes on these forums but none have worked, except reduse the number of crashes after i disabled the autosave.
Upgrade to the latest drivers failed somehow, so I decided to make a clean new installation of my PC. Now I have the latest of all my hardware drivers no other program accept Civilizatio IV and it still hang, though not as often as before.
I have the following...
Windows XP Professional, SP2
DirectX 9.0c
Nvidia 6800 128MB, 81.85
1024 MB RAM
AMD Athlon 64 3200+ 2.2GHz
The game and graphics is beutifull and runs very smothe (with one accepting, the globe view is distorted sometimes) untill it freezes up and I have to reboot, or it reboot by itself or rarely it may crash to desktop with an error message of something going wrong with a file called 'nv4_disp.dll'.
I have given upp hope now, must wait for a patch. The game crashes from 5-30 minutes into the game right now.