delayed job - NameError: uninitialized constant Rails with Rails.root in rails 3.2 -

getting following error while executing environment.rb

c:\railsproject>jruby script/delayed_job start nameerror: uninitialized constant rails_root   const_missing @ org/jruby/rubymodule.java:2647          (root) @ c:/railsproject/config/environment.rb:20         require @ org/jruby/rubykernel.java:1062          (root) @ script/delayed_job:3 

environment.rb contains following code

# sure restart server when modify file  require "rubygems" require 'memcache' if env['local'] == 'y'    require "bundler/setup" end  # uncomment below force rails production mode when # don't control web/app server , can't set proper way # env['rails.env'] = 'production'  # specifies gem version of rails use when vendor/rails not present rails_gem_version = '3.2.13' unless defined? rails_gem_version enable_facebook = false # bootstrap rails environment, frameworks, , default configuration    dir["#{rails.root}/lib/integration/*.rb"].each | file|   require file end   # initialize rails application railsproject::application.initialize! 

i using rails 3.2.13 version.
please me on this?