Using IIS 7.5 Express to launch MVC 3 application, gives HTTP Error 404.20 - Not Found

Question

I have an existing MVC3 application and I want to run that using IIS 7.5 express. When I try to do that I get the following error:

HTTP Error 404.20 - Not Found
No default document.
Most likely causes:
•A default document is not configured for the site.
•The URL contains a typographical error.
•Directory browsing is not enabled.

If I create a new MVC application and run that, it works fine. I compared the route maps and did not see any difference For my application:

public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

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

For the sample application:

public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

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

The controller and action mentioned are available.

I also looked at applicationhost.config file and saw default documents as:

<defaultDocument enabled="true">
            <files>
                <add value="Default.htm" />
                <add value="Default.asp" />
                <add value="index.htm" />
                <add value="index.html" />
                <add value="iisstart.htm" />
                <add value="default.aspx" />
            </files>
        </defaultDocument>

Any suggestions on how to fix this error?