newbie with nested resources on rails 2.0

Scaffold for admin parts of the app is a pain because you have to manually change all the routes used in the generated views.

I would create model, controller and views separately. Since it is easier.

I think your problem is due to nested resource. When you nest, the parent object must be loaded in a before filter before you can perform any CRUD operation on it. Check out the Rails 2.0 screencast:
http://www.akitaonrails.com/2007/12/10/the-first-rails-2-0-screencast-english