We too have pretty much the same issue.  We have clustered Dell PowerEdge 2850 servers w/ 4GB Ram, connecting to a CX300 SAN.  We get the message on all 4 servers whether or not they connect to a database on the SAN or on another stand alone server.  We can run EM from some other non-clustered server and it works fine.  We've tried reinstalling SQL, and even rebuild one of the 2-node clusters from the ground up using different media.  This did not work.  We have escalated this problem to Dell and Microsoft.  Any update to this would be appreciated.  I will update this link if I get an answer.