So I had modded some stuff in the leader xml file when I first got the game. Then later I realized that you were supposed to copy the file to the custom assets folder and mod from there. So restored the original (I made a backup) and moved the modded file to custom assets folder. Everything still worked. It got a little weird when I deleted the custom file and my changes still showed up in the game. I made sure to delete every copy and every backup copy on the machine and still the mods persisted. Finally did a search through the whole computer with any file that had the word 'leader' in it. Apparently it was hiding in a folder labeled 'cache' in my documents\my games\sid meyers... blah blah blah'. The weird thing is I couldn't see the folder with 'show hidden files' turned on, nor could I get to it from a dos prompt. Weird.

Well, it should be there for "show hidden files" - in fact, some people have been deleting it between games as a way of (successfully) preventing crashes.

or go to local disk -> documents and settings -> [user name] -> application data -> firaxis games -> sid's civ4.

And that has all the files

Really? You can see it? Uh oh, I hope I don't have a virus or something.

Not a virus or something, you were just looking in the wrong place. :)

I know this is an old topic, however, I discovered if you edit the Civ4Config file you can set it up so that it won't files into the cache at all.

This way you can mod all you want and not have to worry about things not changing or mysterious crashes happening. ;)

Yeah, I have the cache disabled, myself; the price paid in initialization time is negligible at most.