Here is my code:

 Dim Wresponse As WebResponse = request.GetResponse()
        ' Get the stream containing content returned by the server.
    dataStream = Wresponse.GetResponseStream()
        ' Open the stream using a StreamReader for easy access.
    Dim reader As New StreamReader(dataStream)
       Here is my code: ' Read the content.
    Dim responseFromServer As String = reader.ReadToEnd()
    ' Display the content.
    Dim xml As New XmlDocument
    ' Response.Write(responseFromServer)

    Dim stringWriter As StringWriter = New StringWriter()
    Dim xmlTextWriter As XmlTextWriter = New XmlTextWriter(stringWriter)


    Dim node As XmlNode = xml.SelectSingleNode("/response/result")
    'Response.Write("<br>" & node.InnerText)
When I look at the Source of my browser I have:

  <response xmlns:xsi="" xmlns:xsd="" xmlns="">
         <respmsg>Failed to validate credit card: Unknown Card Type : </respmsg>
When I remove the 'Comment from the last line of my code, I got a an 'Object reference not set to an instance of an object.' error.

I have tried:

Dim node As XmlNode = xml.SelectSingleNode("/response/result")
Dim node As XmlNode = xml.SelectSingleNode("response/result")
Dim node As XmlNode = xml.SelectSingleNode("//response/result")
Dim node As XmlNode = xml.SelectSingleNode("response/result//")
None of them work.
Can anyone tell me where I am going wrong?