undefined method `authenticate_with_http_basic' for #<SessionsController:0xb6c47c44>

I am developing the rails with the flex… I am following the tutorial FLEXIBLE RAILS - PETER ARMSTRONG .
I followed the commands as specified in the tutorial… my rails version is 1.2.3
and the ruby 1.8.6

I created the restful authentication and i specified the authentication…
ruby script\generate authenticated user sessions
…output omitted…

I specified everything… It worked fine upto 500 pages…

later,
class SessionsController < ApplicationController

Be sure to include AuthenticationSystem in Application Controller instead

include AuthenticatedSystem

skip_before_filter :login_required

He told me to comment the authenticated system and use skip_before… i done it and the
" include AuthenticatedSystem " line added to the application.rb file…
now i created the new migration tasks and created the controller

when i need to access the link ’ http://localhost:3000/session
it is throwing the exception

undefined method `authenticate_with_http_basic' for #<SessionsController:0xb6c47c44>

I changed the rails version and tried (2.0.1)
and i reloded the authentication in the application..
and tried in many ways but i can't find the solution
Can Anybody Please help me regarding this error.. where i am doing worng...