Mine works on 7 x64 too. You probably have the dreaded .Net error, where you have so many runtimes installed newer .Net programs - like MusicSphere - go off the deep end. You can try updating your runtimes manually - search Microsoft's site for them - but this is a hard error to troubleshoot and even harder to fix.
The real question is is Musicsphere worth the effort. Whatever coolness it has is, for me, more than offset by the way it completely screws your existing playlists, by adding a million playlists of it's own all starting with MusicSphere_ .
I kind of see why they had to do it that way but it really, really badly interferes with the your existing playlists, because now you have to scroll through 20 or so MusicSphere playlists in the middle of your actual playlists. In iTunes itself it's not bad since they all sit in a folder of their own, but on the iPhone/iPod it's a nightmare of scrolling. I stopped using it because of this.
The only way I see MusicSphere being viable is if/when Apple updates the iPhone to support playlist folders. Or you could take Pioneer's route and say that MusicSphere eliminates the need for your own playlists, which is just the kind of stupid answer I expect.