XXXRes.rrh and XXXRes.rrc are the resource files for the project. They should be in their own resource folder and their own resource project. Their path is C:\foo\bar\resource.
This error occurs when a resource file is being referenced by the application twice. The error occurs when the RRH file has been added to the main project and the resource project has been set as a dependency. It is only required that one of these actions be taken - not both.
To fix the problem, simply remove the dependency that the main application has on the resource project. You can do this by highlighting the main project and selecting ProjectDependencies and clearing the check box associated with the resource project.