It's just not possible that it does NOT load the skin if you did everything like I've outlined in my tutorial. There gotta be some mistake somewhere. Please go step by step carefully through the tutorial again, maybe check out the tutorial on youtube too. If you did everything like that, you are bound to have the black skin. It's not like there's any choice for Spotify, the default skin simply does not exist anymore if you did it correctly and can't be loaded from somewhere else either.