I upgraded to MVC 2, updated all my assemblies (did copy to local also).
I changed my routes to this:
routes.MapRoute(
                "Admin",
                "admin/{controller}/{action}/{id}",
                new { controller = "Admin", action = "index", id = ""},
                new[] { "MyNamespace.Web.Controllers.Admin" } // namespace
            );
 routes.MapRoute(
                "Default",                                              // Route name
                "{controller}/{action}/{id}",                           // URL with parameters
                new { controller = "Home", action = "Index", id = "" },  // Parameter defaults
                new[] { "MyNamespace.Web.Controllers" } // namespace
            );
My controllers look like:
/controllers/admin/ProductController.cs
/controllers/ProductController.cs
I am still getting the error:
he controller name 'Product' is ambiguous between the following types:
MyNamespace.Web.Controllers.Admin.ProductController
MyNamespace.Web.Controllers.ProductController
Should adding the namespace fix this issue?