My COM+ clients raise the RPC server unavailable error when the server is, indeed, unavailable, usually because the COM+ application has been stopped or the server rebooted. I don't know anything about CIS butyou could try starting it while keeping an eye on your COM+ application in the component services viewer to see if CIS is stopping it.

I would have thought (I am looking to test it sometime) that you could trap this error and retry it.