Error on Building 2.3 Interactive SDK sample

[MuhammadWaqar_ul_islam]

I have download version 3 sample and installed 2.3 api
While building the application its gives error on App.xaml.cs
  private void Application_Startup(object sender, StartupEventArgs e)
        {
            string xmlConfig = e.InitParams["xml"]; "Key Not found exception not handled by user code" The given key was  not present in the dictionary             //this.RootVisual = new Page(xmlConfig);
            this.RootVisual = new LightPage(xmlConfig);

            System.Windows.Browser.HtmlPage.RegisterScriptableObject("mySLapp", this.RootVisual);
        }
i have attached a snap shot of this error
please figure  it out what is the problem or what  i m missing

i have version 2.2 which is working fine dont know what's the problem in the version 2.3

[DominiqueBroux]

You have to set the Web project as Startup project.
You might also have to set 'Default.htm' as Start Page.