When using a nested (or embedded) scaffold in ActiveScaffold with Rails 2.3.2 you have the error:
undefined method `render_component'
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.