I'm trying upload photo to picasa i use this C# code

I'm successfully get access token , but when i use it with

            authFactory.Token = googleRespnse.access_token;
            PicasaService service = new PicasaService(authFactory.ApplicationName);

service.RequestFactory = authFactory;

i got error message

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.Script.Serialization; using Google.GData.Client; using Google.Picasa; using Google.GData.Photos; using System.Net; using System.IO;

public partial class _2gplus_move_auth_goauth : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string GKey = System.Configuration.ConfigurationManager.AppSettings["GKey"]; string GSecret = System.Configuration.ConfigurationManager.AppSettings["GSecret"]; string scop = "http://picasaweb.google.com/data/feed/api/user/default/"; string next = System.Configuration.ConfigurationManager.AppSettings["GMyWebSite"] + System.Configuration.ConfigurationManager.AppSettings["GPostAuthorizeRedirectURL"];

    if ((Request["token"] == null) && (Request["error"] == null) && (Request["fromfb"]=="ok"))
    {

        string Url = string.Format("https://accounts.google.com/o/oauth2/auth?client_id={0}&redirect_uri={1}&scope={2}&response_type=code", GKey, next, scop);
        Response.Redirect(Url);

    }
    else if((Page.Request.QueryString["goauth"] != null) && (Page.Request.QueryString["goauth"] == "ok")) //if (Request["goauth"] == "ok")
    {
        if ((Page.Request.QueryString["code"] != null) && (Page.Request.QueryString["code"] != ""))
        {
            string code = Page.Request.QueryString["code"];
            string link = string.Format("https://accounts.google.com/o/oauth2/token");
            string parm = string.Format("client_id={0}&client_secret={1}&redirect_uri={2}&code={3}&grant_type=authorization_code", GKey, GSecret, next, code);
            string response = webFetch(link, parm);

            JavaScriptSerializer js = new JavaScriptSerializer();
            GooGleRespnse googleRespnse=js.Deserialize<GooGleRespnse>(response);

            GAuthSubRequestFactory authFactory = new GAuthSubRequestFactory("lh2","exampleCo-exampleApp-1");
            authFactory.Token = googleRespnse.access_token;
            PicasaService service = new PicasaService(authFactory.ApplicationName);
            service.RequestFactory = authFactory;

            string username = "default";
            AlbumEntry newEntry = new AlbumEntry();
            newEntry.Title.Text = "New album";
            newEntry.Summary.Text = "This is an album";
            AlbumAccessor ac = new AlbumAccessor(newEntry);
            ac.Access = "public";

            Uri feedUri = new Uri(PicasaQuery.CreatePicasaUri(username));

            PicasaEntry createdEntry = (PicasaEntry)service.Insert(feedUri, newEntry);


        }
        else
        {
            Server.Transfer("gonotoauth.aspx");
        }
        Session["google_access_token"] = Request["access_token"];

    }
}

private string webFetch(string link, string parameter)
{
    string responseFromServer = "";
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(link);
    request.Method = "POST";
    byte[] byteArray = System.Text.Encoding.UTF8.GetBytes(parameter);

    request.ContentType = "application/x-www-form-urlencoded";
    request.ContentLength = byteArray.Length;
    Stream dataStream = request.GetRequestStream();
    dataStream.Write(byteArray, 0, byteArray.Length);
    dataStream.Close();

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();

    if (HttpStatusCode.OK == response.StatusCode)
    {
        dataStream = response.GetResponseStream();
        StreamReader reader = new StreamReader(dataStream);
        responseFromServer = reader.ReadToEnd();
        response.Close();
    }

    return responseFromServer;
}
class GooGleRespnse
{
    public string access_token  {get;set;}
    public string expires_in    { get; set; }
    public string refresh_token { get; set; }
}

}

I might not be understanding your question, but I don't see how this GWT OAuth 2.0 library has anything to do with failed access in a C# app?

Also, it looks like you're using the access token to get data from the Picasa GData API, which doesn't support OAuth 2.0, just OAuth 1.0a.