Try this. Go into "C:\Program Files\EMC\Navisphere Agent" and create a agentid.txt file. On the first line enter the FQN of the host and on the second line enter the host's IP address.
I have a Windows 2008R2 Cluster that keeps going back to "unmanaged".  I know all the initiators are connected properly.  What is happening though is that the host initiators keeps losing my cluster nodes primary static IP address and it picking up the "Microsoft Failover Virtual Cluster" adaptor.  I have the laatest agents on the clustered nodes.  Does anyone have any idea to get this to stop?  I did go into "advanced mode in on the server and checked the bindings and they are correct.  I dont even see the failover virtual adaptor in the Adaptor Settings on the server anyways.  Anyone?
Host Agent Not Reachable or connection registered manually or with Unisphere 
Server Utility