Hi I'm trying to get the html code of certain webpage, I have a username and a password that are correct but i still can't get it to work, this is my code:

private void buttondownloadfile_Click(object sender, EventArgs e)
{
    NetworkCredentials nc = new NetworkCredentials("?", "?", "http://cdrs.globalpopsvoip.com/0000069/20091229/20091228_20091228.CDR");   
    WebClient client = new WebClient();

    client.Credentials = nc;
    String htmlCode = client.DownloadString("http://cdrs.globalpopsvoip.com/0000069/20091229/20091228_20091228.CDR");

    MessageBox.Show(htmlCode);
}

The MessageBox is just to test it, the problem is that every time I get to this line:

String htmlCode = client.DownloadString("http://cdrs.globalpopsvoip.com/0000069/20091229/20091228_20091228.CDR");

I get an exception:

The remote server returned an error: (401) Unauthorized.

How do I fix this?