Particular/NServiceBus — pull request #1598 by fergusontom (2013-09-30 09:36:36+00:00)
Title: Expanding message registration exception message as it is a little misleading

The exception message states that the messages must implement, IMessage, IEvent or ICommand however this may not have been the cause of the exception. If the user has configured NSB such that the message types have never been registered (e.g. NSB has not scanned the required assembly) then they will also get this error message even though their messages implement the correct interfaces.