Trying to give something back to the Community...
You might want to check out the two hitfixes detailed in this article:
956589 (http://support.microsoft.com/kb/956589/ ) Description of the Hyper-V update for issues that may occur when you manage the Hyper-V role on the 64-bit editions of Windows Server 2008 by using SCVMM
956774 (http://support.microsoft.com/kb/956774/ ) A Background Intelligent Transfer Service (BITS) client cannot handle files that have paths that contain the volume GUID in Windows Server 2008 or in Windows Vista
Read the complete post at http://wmug.co.uk/blogs/cliffs_blog/archive/2009/02/12/scvmm-kb-962941-recommended-hotfixes-for-system-center-virtual-machine-manager-2008.aspx