FileUpload System.Net.ProtocolViolationException

Hallo ich bekomme bei einem Fileupload in einer Zeile eine: System.Net.ProtocolViolationException

Diese habe ich fett markiert.

   private static string UploadPicture(string pageURL, string uid, string auth_key, string picture_path)
        {
            Functions.Logger.Writelog("Upload URL:" + pageURL,"Info","GetPageForLink");

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(pageURL);
            HttpWebResponse response;
            StreamReader sr;
            string result = "";

            //request.AllowAutoRedirect = false;
            //request.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";

            request.Method = "POST";
            byte[] byteArray = PictureToByteArray(picture_path);
            request.ContentType = "multipart/form-data";
            request.ContentLength = byteArray.Length;
            try
            {

                Stream dataStream = request.GetRequestStream();

                dataStream.Write(byteArray, 0, byteArray.Length);

                dataStream.Close();

             response = (HttpWebResponse)request.GetResponse();

           [b]        sr = new StreamReader(response.GetResponseStream());[/b]

                result = sr.ReadToEnd();

                response.Close();
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.Write("Fehler:" + e.ToString());
            }
            System.Diagnostics.Debug.WriteLine("Response Upload:" + result);
            return result;
        }

1.Was ist hier der Grund?

2.Wie kann ich das machen, dass statt einem File, ein Image hochgeladen wird ohne dieses speichern zu müssen?

System.Net.WebClient Client = new System.Net.WebClient();
Client.Headers.Add("Content-Type", "binary/octet-stream");
byte[] result = Client.UploadFile(pageURL, "POST", picture_path);
string s = System.Text.Encoding.UTF8.GetString(result, 0, result.Length);
return s;

Gleicher Fehler

Grüsse,