Problem
When using a nested (or embedded) scaffold in ActiveScaffold with Rails 2.3.2 you have the error:

undefined method `render_component'

Solution
According to the issue here, in Rails 2.3 the render_component has been removed.

Install the render_component from:

script/plugin install git://github.com/lackac/render_component.git -r rails-edge

and restart your server, and it should be working.