The Hyper-V team has released RC1 of our virtualization platform (you can ready more about it here). Due to some necessary and important interface changes made by the Hyper-V team, the recently released beta of SCVMM 2008 doesn't work correctly with Hyper-V RC1. Needless to say, we're working on a patch and plan to fully support RC1 and I'll update everyone on time lines once we have them nailed. Our goal is to make an update available within a couple of weeks once we get a chance to fix some of the breaking bugs and re-test a bunch of our functionality. Rest assured that our test team is on top of this.
We could have "held" the Hyper-V RC1 release until these SCVMM issues were addressed but in the interest of ensuring our partners (who are also dependent upon the interfaces) get equal and sufficient time to address the changes, we pulled the trigger. It also allows you to begin testing the latest RC and as you get ready to roll it out more broadly, SCVMM will be ready to support you.