Did check the Enable All Controllers box in Big Box? If you have more then one controller connected at a time and don't enable it only the first pair controller will be able to use BB.
For some reason I can't get this to work. Nothing happens when I go to apply it as my theme. It just reverts to the default theme. I did make sure that I am running the latest 10.0 version so I do not know what else it could be.