I bought Vanilla Civ IV in 2005 if I'm not mistaken. Since then, I never bought anything related to civ, and that's part of my philosophy: I'll only buy a game if it's worth it and I have already played it. Also, I won't buy expansions because this market strategy is ridiculous.
And I never had problems with mods. Everything in computers has a way of fixing.
So tell us Noob, where is your CIV installed? Did you install each one or the gold edition?
The normal way of making a mod playable is:
- Download it fully (be sure no corrupted zip files are present);
- Place it under ...\Beyond the Sword\Mods folder;
- Be sure the folder you're placing is with its correct name;
To fix the first one, simply check the zip file when it's downloaded. Normally just opening it will tell you if it's corrupted or not.
The second one is the tricky one. Normally you have 2 Beyond the Sword folders in your pc, one inside your installation address, and the other under Documents (or My Documents). The right one is the one on your installation adress. The one under My Documents is where your saves and screenshots are saved. There is also a hidden folder of Beyond the Sword in AppData (also a hidden folder), but that should be ignored. If you installed the Gold Edition it's fine, if not you may have messed the locations on the installation process. It's recommended that your installation adress be inside of Program Files, if it's the only Program Files folder you have, or Program Files x86 if you have both Program Files folders. Normally is the default installation adress when you attempt to install the game.
The third one is rare but may occur. If you put a folder on Mods called "DoC" it won't work. The DoC folder must be called "RFC Dawn of Civilization". Also you can't make a DoC folder under Beyond the Sword\Mods that has RFC Dawn of Civilization inside of it like Beyond the Sword\Mods\DoC\RFC Dawn of Civilization.
So for example, if I want to reach the Assets folder of my DoC, I have to come to this exact adress:
C:\Program Files (x86)\2K Games\Firaxis Games\Sid Meier's Civilization 4 Complete\Beyond the Sword\Mods\RFC Dawn of Civilization\Assets
If there is anything different of the bolded part on your computer, then it's wrong.
So if you can bring some info here we may help you to install mods on your civ again.