help - updated from 1.2.5 to 1.2.6 and getting undefined method 'session=' for ActionController::base

i start the server but it exits right away,

I ran the rake to update and changed the version string in config.rb.
Any thoughts on this matter would be appreciated.

i imagine that it has something to do with the session, but i am not
able to figure it out.

my config/config.rb has the following

config.action_controller.session = {
:session_key => 'c3_rails_session',
:secret =>'a_big_string '
}
RAILS_GEM_VERSION = '1.2.6'

my versions are
rails 1.2.6
ruby 1.8.5 (open bsd 4.1)

my application.rb controller

class ApplicationController < ActionController::Base
  helper :all # include all helpers, all the time

  # See ActionController::RequestForgeryProtection for details
  # Uncomment the :secret if you're not using the cookie session store
  protect_from_forgery # :secret => '3ac52b38782bce94aa5b8b39873f2052'
  # Be sure to include AuthenticationSystem in Application Controller
instead
  include AuthenticatedSystem
  # If you want "remember me" functionality, add this before_filter to
Application Controller
  before_filter :login_from_cookie

end

You might be using 2.0 by accident. Are you using the newest version
of boot.rb?