There isn't enough info to say exactly what is wrong but here are a few things to keep in mind.
- You cannot listen for routeNotification within the same module that sent it. Routes only go to other modules
- Check that you are sending to the appropriate module in the "to" field or that you are sending to *
- Double check that you have the correct naming convention for a respondTo method. Your example of receiveMessage would become respondToReceiveMessage
- Check that you have properly assigned a defaultRouter to all your modules.
- Make sure your mediator is extending the Fabrication appropriate mediator and not the PMVC one.