The Parallels website now warns that it is not compatible with the Mac Pro:
"At the moment Parallels Desktop doesnâ€™t run on Mac Pro. Weâ€™ll provide an updated version that will function on Mac Pro soon. Click here to sign for Parallels news and stay updated about this issue".
However, they claim there is a patch in development. This is great news. Let's hope that they can pull it off. If not, this could be a serious blow to Apple's quest to capture some of the PC crowd with a mac that can run windows.