将JSON endpoints 添加到WCF Silverlight RIA服务后出错

我正在尝试使用此处的信息将json endpoints 添加到现有的WCF RIA Silverlight服务：

http://blogs.msdn.com/b/deepm/archive/2010/05/14/silverlight-tv-episode-26-exposing-soap-json-and-odata-endpoints-from-ria-services.aspx

但是，当我在调试中启动项目时，我得到了一个

远程服务器返回错误：NotFound .

Silverlight中的错误 .

WCF Trace说：

System.ServiceModel.ServiceActivationException：由于编译期间发生异常，无法激活服务'/Services/CTCT-KronosNameManagement-Web-Services-BPAuthenticationDomainService.svc' . 异常消息是：无法加载文件或程序集'Microsoft.ServiceModel.DomainServices.Hosting，Version = 4.0.0.0，Culture = neutral，PublicKeyToken = 31bf3856ad364e35'或其依赖项之一 . 系统找不到指定的文件.. ---＆gt; System.IO.FileNotFoundException：无法加载文件或程序集“Microsoft.ServiceModel.DomainServices.Hosting，Version = 4.0.0.0，Culture = neutral，PublicKeyToken = 31bf3856ad364e35”或其依赖项之一 . 该系统找不到指定的文件 . 在System.RuntimeTypeHandle.GetTypeByName（String name，Boolean throwOnError，Boolean ignoreCase，Boolean reflectionOnly，StackCrawlMarkHandle stackMark，IntPtr pPrivHostBinder，Boolean loadTypeFromPartialName，ObjectHandleOnStack type）at System.RuntimeTypeHandle.GetTypeByName（String name，Boolean throwOnError，Boolean ignoreCase，Boolean reflectionOnly， System.ServiceModel上的System.Type.GetType（String typeName，Boolean throwOnError）处的System.RuntimeType.GetType（String typeName，Boolean throwOnError，Boolean ignoreCase，Boolean reflectionOnly，StackCrawlMark＆amp; stackMark）中的StackCrawlMark＆amp; stackMark，IntPtr pPrivHostBinder，Boolean loadTypeFromPartialName）位于S的System.ServiceModel.ServiceHostBase.InitializeDescription（UriSchemeKeyedCollection baseAddresses）的System.ServiceModel.DomainServices.Hosting.DomainServiceHost.CreateDescription（IDictionary`2＆amp; implementedContracts）的.DomainServices.Hosting.DomainServiceHost.CreateEndpointFactoryInstance（ProviderSettings provider） System.ServiceModel.DomainServices.Hosting.DomainServiceHostFactory.CreateServiceHost上的System.ServiceModel.DomainServices.Hosting.DomainServiceHost..ctor（类型domainServiceType，Uri [] baseAddresses）中的ystem.ServiceModel.ServiceHost.InitializeDescription（类型serviceType，UriSchemeKeyedCollection baseAddresses） ServiceType，Uri [] baseAddresses）在System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost（String constructorString，Uri [] baseAddresses）的System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService（String normalizedVirtualPath，EventTraceActivity eventTraceActivity）处于System.ServiceModel.ServiceHostingEnvironment . System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable（String normalizedVirtualPath，EventTraceActivity eventTraceActivity）中的HostingManager.ActivateService（ServiceActivationInfo serviceActivationInfo，EventTraceActivity eventTraceActivity）---内部异常堆栈跟踪结束---

如果我在web配置中删除 endpoints ，繁荣：它再次工作......当然除了json .

<system.serviceModel>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />
    <domainServices>
      <endpoints>
        <add name="JSON" type="Microsoft.ServiceModel.DomainServices.Hosting.JsonEndpointFactory, Microsoft.ServiceModel.DomainServices.Hosting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
      </endpoints>
    </domainServices>
</system.serviceModel>

我确实安装了WCF Ria Services Toolkit . System.ServiceModel.DomainServices.Hosting.dll版本为4.1.61829.0

任何建议都会非常有帮助 .