InvalidOperationException on getRequestStream in C#(Windows Mobile 6.5)

While trying to upload the video to server i am facing the Invalid Operation exception at getInputStream.Could you please let me know how i can resolve this issue in windows mobile 6.5.

 HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.google.com");
   request.Method = "POST";
        request.Proxy = null;

        try
        {

            Stream requestStream = request.GetRequestStream();
            using (Stream video = File.OpenRead("Path"))
            {
                byte[] buffer = new byte[4096];
                while (true)
                {
                    int bytesRead = video.Read开发者_运维知识库(buffer, 0, buffer.Length);
                    if (bytesRead == 0) break;
                    requestStream.Write(buffer, 0, bytesRead);
                }
            }
        }
        catch (InvalidOperationException ex)
        {
            MessageBox.Show(ex.Message);
        }

I am not even getting the full message displayed.Could you please let me know the procedure to be followed to view the complete message and do i require it to install on my system or mobile device.

Please let me know your valuable suggestions.

Thanks in advance :)

---

When you are opening the File where is "Path" defined? Also, what thread is this being run on?