I have the new 1.3 patch fixed for the latest update to the game, working flawlessly. But how do I change the skins of the heroes? I've got the files but I don't know where to put them. No luck by just putting them into the 'addon' folder. Help would be appreciated.

What are the files called? It's most likely you need to place them in the directory below if you have the Steam version. If you're using GOG version, it's most likely very similar once you get to GameData. Unfortunately, I can't help find it because I don't have the GOG version, only disk, and Steam.

Windows (C:) > Program Files (x86) > Steam > SteamApps > Common > Star Wars Battlefront II > GameData > data > _LVL_PC > SIDE