http://developers.de/blogs/damir_dobric/archive/2010/02/25/wcf-4-0-file-less-activation-error-servicehost-only-supports-class-service-types.aspxWhen working with WCF 4.0 and File-Less Service Activation you may get following error: ServiceHost only supports class service types. Description: An unhandled exception occurred during the execution of the current web request. Please review the stackenCommunityServer 2008 SP1 (Build: 30619.63)