[C#]Youtube API Problem

YouTubeRequestSettings settings =
            new YouTubeRequestSettings("Commenter", "AI39si5aomSV1_sa-VaAU3Wu6tvRAPvclkzaxaoJY2taVz5pE30mDMf_LUYO69z148z4wFpoTHAGYuDEMMissRKCTgZJ0_oYDA");
            YouTubeRequest request = new YouTubeRequest(settings);
            Comment c = new Comment();
            c.Content = "This is my comment.";
            Video video = new Video();
            video.VideoId = "http://gdata.youtube.com/feeds/api/videos/sKZYVcuSITA";
            request.AddComment(video, c);