This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
My gut tells me you should get something like a incompatible version exception. However, I just tried it on some sample RMI code running in different directories on the same computer and it connected fine.