The documentation for the ModuleManifest.xaml shows us how to use <AssemblyPart .. /> to add an assembly to our manifest.
Is there a way to add a file?
The above noted error is raised when you have an IIS WCF service reference in an external module - Prism finds the module's assembly but doesn't find the ServiceReferences.ClientConfig file contained within the module - I blog on the issue
(with a work-around fix) HERE.
Related forum thread