Proxy Authentication Required (407)

I'm using the following code to access a file on the Internet. I'm running it on my PC at work which connects to the Internet through a proxy.

When the code gets to the GetResponse line a Proxy Authentication Required (407) error occurs.

I know this problem has been raised a few times before, but there don't seem to be any answeres out there. Can anybody help?

"username" and "password" in the code are what I use to log onto the network with.

VB Code:

Option Strict On
 
Imports System.Net
Imports System.IO
 
 
Private Sub Button2_Click(ByVal sender As System.Object, _
                              ByVal e As System.EventArgs) Handles Button2.Click
 
        Dim uri As New Uri("http://www.geocities.com/trisuglow/readme.txt")
 
        Dim wreq As HttpWebRequest
        wreq = CType(WebRequest.Create(uri), HttpWebRequest)
 
        Dim cr As New System.Net.NetworkCredential("username", "password")
        wreq.Credentials = cr
        wreq.PreAuthenticate = True
        wreq.Proxy.Credentials = cr
 
        Dim wrsp As WebResponse
        Try
            wrsp = wreq.GetResponse()
 
            Dim s As Stream = wrsp.GetResponseStream
 
            Dim br As New BinaryReader(s)
            MsgBox(s.Length, , "File Length")
 
        Catch wex As WebException
            Debug.WriteLine("Message: " & wex.Message)
            Debug.WriteLine("Response: " & wex.Response.GetResponseStream.ToString)
            Debug.WriteLine("ResponseURI: " & wex.Response.ResponseUri.ToString)
            Debug.WriteLine("Source: " & wex.Source.ToString)
            Debug.WriteLine("Status: " & wex.Status.ToString)
        End Try
 
    End Sub