error message for Shell class

[s moon]

I trid to test Shell class
in my system, windows 2000/ruby version win-1.7.3-8

this is my code: test1.rb

require 'shell'
sh = Shell.new
puts sh.pwd

But I got this error message

c:/ruby/lib/ruby/1.7/shell.rb:267: private method `initialize' called for Shell:
:CommandProcessor:Class (NoMethodError)
from test1.rb:1:in `require'
from test1.rb:1

shell.rb:267 is

CommandProcessor.initialize
CommandProcessor.run_config

What's wrong?


thanks

s.moon