.NET The request was aborted: The connection was closed unexpectedly. HTTPWEBREQUEST

Code
Imports System.Net

Imports System.Text

Imports System.IO



Public Class Form1



    Dim logincookie As CookieContainer



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click



  Dim postData As String = "username=" & Username.Text & "&password=" & Password.Text & "&LoginBTN="

  Dim tempCookies As New CookieContainer

  Dim encoding As New UTF8Encoding

  Dim byteData As Byte() = encoding.GetBytes(postData)



  Dim postReq As HttpWebRequest = DirectCast(WebRequest.Create("http://respawn.ca/login.php"), HttpWebRequest)

  postReq.Method = "POST"

  postReq.KeepAlive = True

  postReq.CookieContainer = tempCookies

  postReq.ContentType = "application/x-www-form-urlencoded"

  postReq.Referer = "http://respawn.ca/login.php"

  postReq.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; ru; rv:1.9.2.3) Gecko/20100401 Firefox/4.0 (.NET CLR 3.5.30729)"

  postReq.ContentLength = byteData.Length



  Dim postreqstream As Stream = postReq.GetRequestStream()

  postreqstream.Write(byteData, 0, byteData.Length)

  postreqstream.Close()

  Dim postresponse As HttpWebResponse



  postresponse = DirectCast(postReq.GetResponse(), HttpWebResponse)

  tempCookies.Add(postresponse.Cookies)

  logincookie = tempCookies

  Dim postreqreader As New StreamReader(postresponse.GetResponseStream())



  Dim thepage As String = postreqreader.ReadToEnd



  RichTextBox1.Text = thepage



    End Sub



End Class