Taken from: http://blogs.vmware.com/kb/2012/09/alert-vsphere-5-1-is-not-compatible-with-any-versions-vmware-view.html

VMware vSphere 5.1 is not currently supported with any versions of VMware View.

vSphere 5.1 is in the process of being certified against VMware View. We recommend that you do not upgrade vSphere above the supported versions listed in the VMware View 5.1 Release Notes.

For further updates and more information on this alert, refer to KB article:
vSphere 5.1 is not compatible with any versions VMware View (2035268).