If you really want to get the MM working on a vista 64 machine you could always build a Virtual machine running 32bit windows. Not a simple youlution but it would work for those that want to take a 64bit laptop to the track.
I have just tried this and it work for me. Have a new computer with Vista, couldn't get Castle link loaded for days. Read only the first post and followed his instructions and the program installed fine. I'll report back after I do some more testing.