dear

i can not use Networkcomms Dll in a Silverlight Application, it return an error at:
ChatMessage messageToSend = new ChatMessage(NetworkComms.NetworkIdentifier, localName, toSend, messageSendIndex++);
the error message is:

System.TypeInitializationException was unhandled by user code
  Message=The type initializer for 'NetworkCommsDotNet.NetworkComms' threw an exception.
  TypeName=NetworkCommsDotNet.NetworkComms
  StackTrace:
       at NetworkCommsDotNet.NetworkComms.get_NetworkIdentifier()
       at ExamplesSLChat.MainPage.SendMessage(String toSend)
       at ExamplesSLChat.MainPage.Button_Click(Object sender, RoutedEventArgs e)
       at System.Windows.Controls.Primitives.ButtonBase.OnClick()
       at System.Windows.Controls.Button.OnClick()
       at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
       at System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)
       at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName, UInt32 flags)
  InnerException: System.MethodAccessException
       Message=Attempt by method 'DPSBase.DPSManager.AddDataProcessor<System.__Canon>()' to access method 'SevenZipLZMACompressor.LZMACompressor..ctor()' failed.
       StackTrace:
            at System.RuntimeMethodHandle.PerformSecurityCheck(Object obj, RuntimeMethodHandleInternal method, RuntimeType parent, UInt32 invocationFlags)
            at System.RuntimeMethodHandle.PerformSecurityCheck(Object obj, IRuntimeMethodInfo method, RuntimeType parent, UInt32 invocationFlags)
            at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
            at DPSBase.DPSManager.AddDataProcessor[T]()
            at NetworkCommsDotNet.NetworkComms..cctor()
       InnerException: 

please help me. thanks