Mono will not fire the next code: I recieve internal server error 500, error writing request error. Code works perfectly under normal .internet.... any ideas why its damaged and just how to repair it?

  public class testService : System.Web.Services.Protocols.SoapHttpClientProtocol

       private string DummySoapRequest = @"<?xml version=""1.0"" encoding=""utf-8""?>
      <soap:Envelope xmlns:soap=""""   xmlns:xsi="""" xmlns:xsd="""">
   <DummyOperation xmlns="""">      

public void SendDummyRequest()
    System.Net.WebRequest req = GetWebRequest(new Uri(Url));
    req.Headers.Add("SOAPAction", "");
    req.ContentType = "text/xml;charset=\"utf-8\"";
    req.Method = "POST";

    using (Stream stm = req.GetRequestStream())
        using (StreamWriter stmw = new StreamWriter(stm))
    System.Net.WebResponse response = req.GetResponse();

Perhaps you have attempted this Visual Studio plugin to ascertain if your code is mono ready? This can be a much better question for stackoverflow ....