Are you getting the following exception:
System.Runtime.Remoting.RemotingException: This remoting proxy has no channel sink which means either the server has no registered server channels that are listening, or this application has no suitable client channel to talk to the server.
Then the chances are you are registering objects before registering the channels. As mentioned in the article Microsoft .NET Remoting: A Technical Overview, at least one channel must be registered with the remoting framework before a remote object can be called. Channels must be registered before objects are registered.
Check if you are issuing Activator.GetObject() call before registering the channels. It would be the cause of problem.