I'm running into the exact same problem with my install, I've tried the rendering fix provided in another thread, no luck.
My PC Specs:
2.4GHz Celeron
512DDR RAM 400MHz
ATI All-In-Wonder 7500 64mb DDR
40GB Maxtor 7200rpm 8mb buffer
C-Media 8038 6-channel Sound Card
16x Memorex DL DVDR/RW +/- Burner
I have all the latest drivers installed for all hardware.
It seems like some textures are missing/failed to load. I've noticed that every-so-often, when you load the game, a patch or strip of the screen will show the terrain, when you scroll the map, that same area scrolls with the map when you browse elsewhere. Also, the mini-map shows that the area should be visible (it's highlighted to your civs' game color) but yet you still can't see the terrain. Excluding these problems, the game does run smoothly but it's almost impossible to play without the terrain view, all you can see are the icons for the resources.
Any help with this prob would be GREATLY appreciated!