If you've been testing out the latest VSTS 2010/.NET 4.0 CTP, you may or may not have noticed that the CTP is due to expire on December 31, 2008 (screenshot was taken on Dec 15).
We don't have plans to make an updated Rosario CTP before the expiration date. This was an unfortunate oversight when the VPC was created but there is a work around.
Basically, you disable the VPC from syncing it's time with the Host OS.
Check out Jeff Beehler's blog article on how to do it.