I recently created a WCF service (dll) and a service host (exe). I know my WCF service is working correctly since I am able to successfully add the service to WcfTestClient.
To prepare the configration for WCF is hard, and sometimes a service type definition go unnoticed.
I wrote only the namespace in the service tag, so I got the same error.
Do not forget, the service tag needs a fully-qualified service class name.
For the other folks who are like me.