I'm trying to run Catalog Integration Services for Commerce R3, I have installed it using the installation instructions as given in the SDK documentation, but the service page (CatalogService.svc) is giving the following error: 

System.InvalidOperationException: An exception was thrown in a call to a WSDL export extension: System.ServiceModel.Description.DataContractSerializerOperationBehavior
contract: http://services.mediachase.com/ecf/50/catalogservice:CatalogService ----> System.Runtime.Serialization.InvalidDataContractException: Type 'Mediachase.Commerce.Catalog.CatalogKey' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute.