Non-broken Rake 0.9.0 RakeFile Example

Rakefile

# Add your own tasks in files placed in lib/tasks ending in .rake,
# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.

require File.expand_path('../config/application', __FILE__)

module ::YourApplicationName
  class Application
    include Rake::DSL
  end
end

module ::RakeFileUtils
  extend Rake::FileUtilsExt
end

YourApplicationName::Application.load_tasks

adding "require 'rake/dsl_definition'" to my rakefile worked for me.
windows 7
rails 3.0.9