I have a fairly fresh installation of vCenter 5.1.0b. The inventory contains one DC which contains two brand new ESXi 5.1 hosts. These hosts comply with all the VSA requirements - 4 NICs, matching RAID storage, etc. Everything is in the same subnet and hosts are configured in DNS. Only the management network has been set up on ESXi. vCenter can see and manage the both ESXi hosts. Installing VSA Manager 5.1.1 seems to complete successfully. The VSA Manager plug-in appears in vSphere client and is enabled. However trying to open the VSA Manager tab shows a very faint progress bar which progresses a couple of times and then ... nothing! (I've tried waiting for an hour just in case!)
I have tried re-starting, re-installing, disabling IPv6 and disbling Windows firewall. There are absolutely no errors in VSAManager.log or in the Windows logs. HP SIM is installed on this server but I've tried disabling all HP services and reinstalling again.
If I could just find an error message somewhere...!