WebSocketProxy throwing exception after moments

     HttpWebRequest Request = (HttpWebRequest)WebRequest.Create("http://mytorlink.onion/uploader.php");

            ProxyConfig Config = new ProxyConfig(IPAddress.Loopback, 8181, IPAddress.Loopback, 3131, ProxyConfig.SocksVersion.Five);

            Request.Proxy = new SocksWebProxy(Config);
            Request.Method = "POST";
            Request.ContentType = "multipart/form-data; boundary=---------------------------" + DateTime.Now.Ticks.ToString("x");
            Request.KeepAlive = false;
            using (Stream requestStream = Request.GetRequestStream())
            {
                using (FileStream fileStream = new FileStream(Application.StartupPath + "\\tor.zip", FileMode.Open, FileAccess.Read))
                {
                    byte[] buffer = new byte[4096];
                    int bytesRead;
                    while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                    {
                        requestStream.Write(buffer, 0, bytesRead);
                    }
                    requestStream.Flush();
                }
            }

            using (HttpWebResponse response = (HttpWebResponse)Request.GetResponse())
            {
                using (var reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("utf-8")))
                {
                    string contenu = reader.ReadToEnd();
                    Console.WriteLine(contenu);
                }
            }
            Console.ReadLine();

After some moments from connecting to TOR (it connects and works, i can get responses) it throws a NullReferenceException Client.cs at Org.Mentalis.Proxy.Client line 189. I do not know how does this happen. But it does connect, get response like nothing happens. After some moments it throws this exception. I am using SocksWebSocket for it as you can see from my code.