A.Giraud, I am having this same issue using VCenter 5.1 and I am running the Dell MUMC software on a Windows Server 2008 RC2 VM. After struggling for 2 days I finally called both VMware and Dell technical support.  Dell says this is a known issue with VMware Vcenter 5.1 and AD integration.  They are currently working on a solution to this issue.  If anyone else has gotten the MUMC software to work with VCenter 5.1please chime in because as it now stands there is allegedly no work around known to Dell.
Hello everyone, To make it quick: We recently changed the whole infrastructure, including a new UPS: (1920w) [URL] . We've got a VMware Essential Plus edition (with a Vcenter) and wanted to use the MUMC to manage the correct shutdown of VMs and ESX hosts. MUMC is installed on the same VM as the Vcenter, windows firewall is disabled (Vcenter default ports are used). The main problem is when we add the Vcenter to the virtualization module (tried login with domain\user or user[NAME]). We can see this error in the log file: Error The Vcenter plugin has never showed up in the Vcenter. Any great idea how to solve this will be welcomed.. we didn't find any suggestion or detail concerning this error. (I can give more details if it can help)
MUMC and VCenter Plugin