java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: java.lang.ClassNotFoundException: ServicesTableau

That class isn't available on the CLASSPATH of the RMI Registry. The simplest way to fix it is to start the Registry in the same JVM, via LocateRegistry.createRegistry(). Store the result in a static field.

This happened to me because I didn't run rmiregistry in the same directory as the server.