Error: The type or namespace oAuthTokenResponse could not be found

Hi

I am getting error - The type or namespace oAuthTokenResponse  could not be found.

if(Request["oauth_token"] == null)
{
    oAuthTokenResponse reqtoken = oAuthUtility.GetRequestToken(
        oauth_consumer_key,
        oauth_consumer_secret,
        Request.Url.AbsoluteUri
    );
    Response.Redirect(string.Format("http://twitter.com/oauth/authorize?oauth_tokrn={0}", reqToken.Token));
}
else
{
    string requestToken = Request["oauth_token"].ToString();
    string pin = Request["oauth_verifer"].ToString();
    var tokens = OAuthUtility.GetAccessToken(
        oauth_consumer_key,
        oauth_consumer_secret,
        requestToken,
        pin);
    OAuthTokens accesstoken = new OAuthTokens()
    {
        accesstoken = tokens.Token,
        AccessTokenSecret = tokens.TokenSecret,
        Consumer_Key = oauth_consumer_key,
        ConsumerSecret = oauth_consumer_secret,
    };
    TwitteResponse<TwitterStatus> response = TwitterStatus.Update(accesstoken, "Testing!");
    if(response.Result == RequestResult.Success)
    {
        Response.Write("we did it");
    }
    else
    {
        Response.Write("it's all bad");
    }
}

How we can upload video with below code

Thanks