Doom 3 won't load mod files from the "base" folder

I have no idea what I'm doing wrong. I downloaded the Wulfen Texture Pack for Doom 3 and followed the directions (copy the "textures", "models", and "parallax occlusion mapping" folders into the "base" folder). As far as I know, Doom 3 should load these files when I start up the game. The vanilla Doom 3 textures are still showing up, however. Does anyone know what I need to change? I'm running Windows 7 64-bit, if it matters.

I personally never put anything in the base folder. I think editing the base folder is akin to editing an idTech 1 IWAD; just not a good idea. Perhaps you can try restoring your base folder to default and stick the mod in it's own folder.