DPM 2010 backups of Hyper-V CSV Failover Cluster causes VMs to 'stop'

I have recently setup my DPM server to backup my failover cluster via this linkhttp://technet.microsoft.com/en-us/library/ff634192.aspx &http://support.microsoft.com/kb/2473194.  I made these modifications because I was having VM backups fail because of a VSS error "Failed to prepare a Cluster Shared Volume (CSV) for backup as another backup using the same CSV is in progress"  

After making these changes - My VMs now randomly stop when being backed up.  I have a 3 node cluster running Server 2008 R2 NON SP1.  Any help is greatly appreciated.

Zach