now the answer,
I think best thing you can do is delete your civ instalation using the add/remove programs, than manual delete EVERYTHING in your civ4 map (also the civ4 map itself), also in you documents map (my games)
download the latest (official) patch for the game. (3.19)
I don't now wich version you have, if you have the all into one that is easy, otherwise, start with civ4, than civ4: Warlors, than civ4 BTS.
install the lastest patch for the game, and play the game I hope.