title: Error when in Silverlight when trying to reach an RIA Services endpoint
body: <p>I created a Ria services endpoint. Silverlight passes data into the RIA Services. The end point then writes/updates this data to the file system. We are experiencing the following exception:</p>
  
  <blockquote>
    <p>System.ServiceModel.DomainServices.Client.DomainOperationException:
    Invoke operation
    'ModifyLogiDashletXmlFile' failed.
    Exception of type
    'System.ServiceModel.DomainServices.Client.DomainOperationException'
    was thrown.    at
    Phoenix.UI.SL.Infrastructure.Services.LogiReportService.&lt;&gt;c_<em>DisplayClass8.&lt;ModifyLogiDashletXmlFile&gt;b</em>_7(InvokeOperation
    operation)    at
    System.ServiceModel.DomainServices.Client.InvokeOperation.&lt;&gt;c_<em>DisplayClass4<code>1.&amp;lt;Create&amp;gt;b__0(InvokeOperation</code>1 arg)    at
    System.ServiceModel.DomainServices.Client.InvokeOperation`1.InvokeCompleteAction()
    at
    System.ServiceModel.DomainServices.Client.OperationBase.Complete(Exception
    error)    at
    System.ServiceModel.DomainServices.Client.InvokeOperation.Complete(Exception
    error)    at
    System.ServiceModel.DomainServices.Client.DomainContext.CompleteInvoke(IAsyncResult
    asyncResult)    at
    System.ServiceModel.DomainServices.Client.DomainContext.&lt;&gt;c</em>_DisplayClass38.&lt;InvokeOperation&gt;b__34(Object )</p>
  </blockquote>
  
  <p>the attributes on the class:</p>
  
  <pre><code>[EnableClientAccess(RequiresSecureEndpoint = true)]
      [LinqToEntitiesDomainServiceDescriptionProvider(typeof(PhoenixEntities))] // IMPORTANT: Must have this because we are returning/passing EF Entities from Phoenix Context
      [RequiresAuthentication]
      public class LogiReportService : DomainService
      {
  ...
  
  }
  </code></pre>
  
  <p>The entry method:</p>
  
  <pre><code>[Invoke]
  public void ModifyLogiDashletXmlFile(IEnumerable&lt;ParameterNameValuePair&gt; paramNameValuePairs, Guid clientId, string dashletInstanceId)
  {
  
      // Validate Client is has a valid relationship to the User (i.e. no disabled)
      if (this.PhoenixUser.MembershipClientIds.Contains(clientId))
      {
         ModifyLogiXmlFile(PhoenixUser.UserId, clientId.ToString(), dashletInstanceId, paramNameValuePairs);
      }
  }
  </code></pre>
  
  <p>What's baffling is other endpoints work fine. The differences between this endpoint and the other is this one writes and reads files from the file-system. The app-domain user has full-rights and the error returned does not appear to be a permissions issue.</p>
  
  <p>All idea's are welcomed. I'm hitting up against a wall with this issue.</p>