I'm using htmlagilitypack to extract some data from a website but I can't figure out what issue happen?

string Url = "http://ift.tt/2dx8fR7";
        HtmlAgilityPack.HtmlDocument htmlDoc = new HtmlWeb().Load(Url);

         foreach ( var node in htmlDoc.DocumentNode.SelectNodes("/html/body[@class='body  ']/div[@class='body_main container']/div[@id='main_container']/div[@id='main-row']/div[@id='content-column']/div[@id='movies-collection']/div[@class='mb-movies list-view']/div[@class='mb-movie']"))
        {
            string movieTitle = node.InnerText;
            richTextBox1.Text += movieTitle + System.Environment.NewLine;
        }

I want to extract all movies title from this URL navigating XPath. VS says that I have no object reference. Why? Can you try for me in this particulary case?