silverlight error

void Welcome_Loaded(object sender, RoutedEventArgs e) 
{ 
     Srvc.MyServiceClient proxy = new SL_SessionMgmt.Srvc.MyServiceClient(); 
     proxy.ReturnUserCompleted += new EventHandler<SL_SessionMgmt.Srvc.ReturnUserCompletedEventArgs>(proxy_ReturnUserCompleted); 
     proxy.ReturnUserAsync(); 
}

i'm getting an error in this code at "Srvc" and "SL_SessionMgmt" saying that there is no such type or namespace found....