Warren here with a quick announcement for those that are running DFSR environments that have Windows Server 2003 R2 and Windows Server 2008 or Windows Server 2008 R2. Microsoft has released a hotfix that you should install on your Windows Server 2003 R2 DFSR servers to address a protocol interoperability issue with up-level DFSR servers. The hotfix is described in KB 2462352:

DFSR fails from a computer that is running Windows Server 2008 R2 to a computer that is running Windows Server 2003 R2
http://support.microsoft.com/default.aspx?scid=kb;en-US;2462352

Warren Williams