'rake routes' gives error

when I run 'rake routes' I get the following error:

rake aborted!
undefined method `session=' for ActionController::Base:Class

I believe the new cookie based sessions in environment.rb are causing
the error:

config.action_controller.session = {
:session_key => '_myapp_session',
:secret => 'getyourownsecretkey'

Isn't this supposed to be the default in rails? When I comment it out
the rake works. Is this a bug problem?

Oh, and I'm on rails 1.2.5

Duh, the session method is only for 'edge' rails. Rails 1.2.5 doesn't
have it yet.