User "invoke" to test Action Web Services in Rails 2.0


I found this great plugin that "ports" AWS to Rails 2.0. But I'm having one problem. I am unable to use the "invoke" scaffold to test my new API methods. When I try to access /myapicontroller/invoke I get:

ActionController::MissingTemplate (Missing template /Users/misleb/rails/homeroom/vendor/plugins/action_web_services/lib/action_web_service/templates/scaffolds/layout.rhtml

But that file is there. What's going on?

I got the plugin from here:

Someone also posted a question about the invoke method. They didn't get a response.