You wil need to add the following line to the Global.asax.cs file:

public class MvcApplication : System.Web.HttpApplication
{
  public static void RegisterRoutes(RouteCollection routes)
  {
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
    routes.IgnoreRoute("{resource}.ashx/{*pathInfo}"); <-- Add this line

    routes.MapRoute(
      "Default", // Route name
      "{controller}/{action}/{id}", // URL with parameters
      new { controller = "Home", action = "Index", id = "" } // Parameter defaults
    );

  }

   protected void Application_Start()
  {
    RegisterRoutes(RouteTable.Routes);
  }
}

Even though you have a later version of the .Net Framework installed you may still need to tell your web application to use the later version of ASP.NET. To do this: 1. Select the properties dialog for the web site or virtual folder in IIS 2. Select the ASP.NET tab 3. Select version 2.0 (or above) as the ASP.NET version

You will need to copy the file system.web.extensions.dll from the DbNetSuite bin folder to your application bin folder