I figured this out after speaking with Dell support.  This error was because I was trying to map a volume to a cluster where a mapping for one of the servers in said cluster already existed for the volume.  I had to remove the individual server mapping before creating the map to the cluster.
I'm getting an error when I try to map a volume to a cluster of servers in Unisphere.  I can map the volume to a server within the cluster, just not the cluster itself.    [IMAGE]
Error in Unisphere when mapping a volume to cluster