The system requirements say "DirectX 9.0c-compatible 64 MB video card with Hardware T&L support",
Yours is an on board graphics chip if memory serves me right - if so, you may have a problem there as I think that chip does not support all the Directx 9 features. The memory side is ok, (256RAM & 64Mb video), but need to verify if the game supports this chip, I have a feeling it wont. I hear you re 254, but maybe you will get away with it albeit it is 2mb adrift
Suggest you pop back in the morning, if no further info on this thread - repost with the Title "Does Civ IV support Intel(R) 82845G/GL/GE/PE/GV Graphics Controller",and one of the guys with definitive knowledge of that chip will pick it up. I am almost certain it does not support T&L, if true you will not be able to run it properly
Regards
Zy