Forms Authentication cookies problem

Hello all,

I have recently setup SSRS with form based authentication using the sample. So far everything is working fine but now I have bumped into a problem. I have created a page on which a user can register a new user in the database. It works fine but now I want that single page to be only accessible by a user with a certain username. This is where the problem arises.

For some reason 

HttpContext.Current.User.Identity.Name;

Returns a null value. It seems as if as soon as a user logs in on uilogon.aspx the browser has authenticated the user but doesn't store any of the user info in a cookie. This conclusion is also based on the fact that creating a separate folder for the register page and setting authorization values in web.config in that folder redirects my logged in user to an error page saying he/she is not authorized. The way a cookie is being stored is the same as the sample code:

public class ReportServerProxy : ReportingService2010
   {
      protected override WebRequest GetWebRequest(Uri uri)
      {
         HttpWebRequest request;
         request = (HttpWebRequest)HttpWebRequest.Create(uri);
         // Create a cookie jar to hold the request cookie
         CookieContainer cookieJar = new CookieContainer();
         request.CookieContainer = cookieJar;
         Cookie authCookie = AuthCookie;
         // if the client already has an auth cookie
         // place it in the request's cookie container
         if (authCookie != null)
            request.CookieContainer.Add(authCookie);
         request.Timeout = -1;
         request.Headers.Add("Accept-Language",
            HttpContext.Current.Request.Headers["Accept-Language"]);
         return request;
      }

      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2201:DoNotRaiseReservedExceptionTypes")]
      protected override WebResponse GetWebResponse(WebRequest request)
      {
         WebResponse response = base.GetWebResponse(request);
         string cookieName = response.Headers["RSAuthenticationHeader"];
         // If the response contains an auth header, store the cookie
         if (cookieName != null)
         {
            Utilities.CustomAuthCookieName = cookieName;
            HttpWebResponse webResponse = (HttpWebResponse)response;
            Cookie authCookie = webResponse.Cookies[cookieName];
            // If the auth cookie is null, throw an exception
            if (authCookie == null)
            {
               throw new Exception("Authorization ticket not received by LogonUser");
            }
            // otherwise save it for this request
            AuthCookie = authCookie;
            // and send it to the client
            Utilities.RelayCookieToClient(authCookie);
         }
         return response;
      }

      private Cookie AuthCookie
      {
         get
         {
            if (m_Authcookie == null)
               m_Authcookie =
               Utilities.TranslateCookie(
                  HttpContext.Current.Request.Cookies[Utilities.CustomAuthCookieName]);
            return m_Authcookie;
         }
         set
         {
            m_Authcookie = value;
         }
      }
      private Cookie m_Authcookie = null;
   }

   [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]
   internal sealed class Utilities
   {
      internal static string CustomAuthCookieName
      {
         get
         {
            lock (m_cookieNamelockRoot)
            {
               return m_cookieName;
            }
         }
         set
         {
            lock (m_cookieNamelockRoot)
            {
               m_cookieName = value;
            }
         }
      }
      private static string m_cookieName;
      private static object m_cookieNamelockRoot = new object();

      private static HttpCookie TranslateCookie(Cookie netCookie)
      {
         if (netCookie == null)
            return null;
         HttpCookie webCookie = new HttpCookie(netCookie.Name, netCookie.Value);
         // Add domain only if it is dotted - IE doesn't send back the cookie 
         // if we set the domain otherwise
         if (netCookie.Domain.IndexOf('.') != -1)
            webCookie.Domain = netCookie.Domain;
         webCookie.Expires = netCookie.Expires;
         webCookie.Path = netCookie.Path;
         webCookie.Secure = netCookie.Secure;
         return webCookie;
      }

      internal static Cookie TranslateCookie(HttpCookie webCookie)
      {
         if (webCookie == null)
            return null;
         Cookie netCookie = new Cookie(webCookie.Name, webCookie.Value);
         if (webCookie.Domain == null)
            netCookie.Domain =
               HttpContext.Current.Request.ServerVariables["SERVER_NAME"];
         netCookie.Expires = webCookie.Expires;
         netCookie.Path = webCookie.Path;
         netCookie.Secure = webCookie.Secure;
         return netCookie;
      }

      internal static void RelayCookieToClient(Cookie cookie)
      {
         // add the cookie if not already in there
         if (HttpContext.Current.Response.Cookies[cookie.Name] == null)
         {
            HttpContext.Current.Response.Cookies.Remove(cookie.Name);
         }

         HttpContext.Current.Response.SetCookie(TranslateCookie(cookie));
      }
   }
}

This leaves me clueless as to where the problem is located and how to fix it..