One of the supposedly "GREAT" things about Vista, is that is supposed to be able to be able to support/emulate the older OS's including various levels of SP's
I really doubt there is a problem running the updater on vista, if there was they could incorporate an OS checker in the exe, and block anything that is not supported. Just as they have done with flightbook.
This is not really the place to discuss OS's, so I appologise.