I do not have an answer for you, but this error message does seem very similar to an error message I am getting regarding snapshots:
"Finder 'VC:VirtualMachineSnapshot' : unexpected error 'ch.dunes.model.sdk.SDKFinderException: convertToResult() --> Finder 'VC:VirtualMachineSnapshot' : unable to invoke read method : 'name''
Perhaps we are both dealing with the same bug. I reported it to VMWare.
I will let you know if they have anything useful to say.