Problem with website login

[John Anthony]

I am trying to get this application to login in order to gather specific data from within the members area. This is the first time I have done this and I am not sure whats wrong.

The site passes the login like this:
http://www.example.com/Ajax/Users_Login.asp?UserName=NAME&UserPsw=PASS&Remembe rMe=1&LogInLocation=0&BackUrl=0

When this page is loaded it displays a xml file with a welcome message. When I retrieve the requested page it acts like it was not logged in. Any help would be greatly appreciated!

            string loginUri = "http://www.example.com/Ajax/Users_Login.asp";
            string loginData = "?UserName=NAME&UserPsw=PASS&RememberMe=1&LogInLocation=0&BackUrl=0";
            string requestUri = "http://www.example.com/";
            CookieContainer cookieContainer = new CookieContainer();
            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(loginUri);
            req.CookieContainer = cookieContainer;
            req.Method = "POST";
            req.ContentType = "application/x-www-form-urlencoded";
            ASCIIEncoding encoding = new ASCIIEncoding();
            byte[] loginDataBytes = encoding.GetBytes(loginData);
            req.ContentLength = loginDataBytes.Length;
            Stream stream = req.GetRequestStream();
            stream.Write(loginDataBytes, 0, loginDataBytes.Length);
            stream.Close();
            HttpWebResponse res = (HttpWebResponse)req.GetResponse();
 
            req = (HttpWebRequest)HttpWebRequest.Create(requestUri);
            req.CookieContainer = cookieContainer;
            req.Method = "GET";
            res = (HttpWebResponse)req.GetResponse();
            StreamReader sr = new StreamReader(res.GetResponseStream());
            textBox1.Text = sr.ReadToEnd();