Same problem
Updgraded to Leopard on a Intel MacPro, booted into Windows via Boot Camp, ran the new drivers installation, rebooted into Leopard, when I tried to start Parallels (using Boot Camp pvs from before Leopard upgrade) got error message stating that Parallels couldn't communicate with one of its drivers and it recommended reinstalling Parallels. Did so and Parallels would start but got the spinning beach ball of death for the parallels Windows and the icon did not show its usual sand running through the hourglass as it started up parallels.
Lawrence
Update: I was finally able to get mine restarted by deleting all of Parallels from the Mac, reinstalling it and then making new Virtual machines. Be sure to reinstall Parallel Tools on your windows OS also.
Last edited: Oct 27, 2007