Error when editing virtual machine properties using vCenter Appliance 5.5

Since installing vCenter Server Appliance 5.5 I have encountered the following error message every time I edit the properties of a virtual machine and click OK, event if I don’t make any changes:

com.vmware.sps.fault.QsConnectionException

The server hasn’t been restarted since installation so I thought I’d try the basics first.  Immediately after the restart I was able to edit VM properties without seeing the message!