Perhaps the primary difference is that you are using a client-server setup, where as I just have a plain vanilla single computer? I have never setup a client-server with MC, or with any application for that matter, so I have no knowledge in that area or useful advice to offer. Maybe do a full uninstall to clear the registry, and then re-installing? Take that cheap advice FWIW, but who knows, its pretty quick and painless (as long as you back up of course!) and may solve the issue.
Hopefully this gets resolved soon for you (and others most likely), as for my money, this is the best enhancement JRiver has made in some time... again, IMHO. I do have a couple of "too easy" ideas to tweak its ease of use, but since they just added this feature, I figure they will be evolving it for the next few months without any need for input from me!