rawline_irb.rb not working on Ruby 1.9.1

C:/Ruby/lib/ruby/1.9.1/irb/input-method.rb:108:in `initialize': undefined method `encoding' for nil:
NilClass (NoMethodError)
        from rawline_irb.rb:26:in `new'
        from rawline_irb.rb:26:in `<module:IRB>'
        from rawline_irb.rb:24:in `<main>'

This is due to the fact that IRB.conf[:LC_MESSAGE] is not set.

The script should be updates as follows:

# ...
module IRB
 	@CONF[:LC_MESSAGES] = Locale.new # <<<
	@CONF[:SCRIPT] = RawlineInputMethod.new
end
IRB.start