This property is not implemented by this class. Error in my project.

[Vijayadhas]

I am following Your Instructions. It was working in my sample project. When i try to implement in my original project i get error.

private void LoginSucceded(string accessToken)
{
var fb = new FacebookClient(accessToken);

        fb.GetCompleted += (o, e) =>
        {
            if (e.Error != null)
            {
                Deployment.Current.Dispatcher.BeginInvoke(() =>
                {
                    MessageBox.Show(e.Error.Message);
                    return;
                });
            }

            var result = (IDictionary<string, object>)e.GetResultData();
            var id = (string)result["id"];

            var url = string.Format("/Views/FacebookInfoPage.xaml?access_token={0}&id={1}", accessToken, id);
            var rootFrame = (App.Current as App).RootFrame;
            Deployment.Current.Dispatcher.BeginInvoke(() =>
               {
                   rootFrame.Navigate(new Uri(url, UriKind.Relative));
               });
        };

        fb.GetAsync("me?fields=id");
    }

In this method i am getting error in this line: fb.GetAsync("me?fields=id");

error..System.NotImplementedException: This property is not implemented by this class.
at System.Net.HttpWebRequest.SetUserAgent(String value)
at System.Net.HttpWebRequest.set_UserAgent(String value)
at Facebook.HttpWebRequestWrapper.set_UserAgent(String value)
at Facebook.HttpWebRequestWrapper.TrySetUserAgent(String userAgent)
at Facebook.FacebookClient.PrepareRequest(HttpMethod httpMethod, String path, Object parameters,
Type resultType, Stream& input, Boolean& containsEtag, IList`1& batchEtags)
at Facebook.FacebookClient.ApiAsync(HttpMethod httpMethod, String path, Object parameters, Type resultType, Object userState)
at Facebook.FacebookClient.GetAsync(String path, Object parameters, Object userState)
at Facebook.FacebookClient.GetAsync(String path)
at TestReactive.com.beno.WP7Client.ViewModels.FacebookViewModel.LoginSucceded(String accessToken)
at TestReactive.com.beno.WP7Client.ViewModels.FacebookViewModel.webBrowser_Navigated(Object sender, NavigationEvPID:0ED1004E TID:0F8A0042 entArgs e)
at Microsoft.Phone.Controls.WebBrowser.FireNavigatedEvent(Uri uri)
at Microsoft.Phone.Controls.WebBrowserInterop.ReversePInvokeThunk.OnNavigated(Int32 webBrowserControlId, String uri)

Please help me to resolve this problem.