There has been discussion about Vista on the DSLRFocus Forum of late, simple answer is it dosen't work with Vista, people are trying, using XPSp2 mode ? (I know nothing about Vista). The main problem is the Camera Drivers, Canon Vista compatable drivers are, I am led to believe, not available within DSLRFocus as yet.
If you are looking for a completely Vista compatable solution, the latest ImagesPlus is completely compatable. Check here:
http://www.mlunsold.com/
Cheers
JohnG