Uninitialized constant RbReadline::Encoding error while running rake for rails 3.0.0 with ruby 1.8.7 app

Got the above error whenever I was executing rake for my new rails 3.0.0 app in Windows 7.

Comment out the following lines from the rbreadline.rb file under C:\Ruby187\lib\ruby\site_ruby\1.8

This is really a huge file, opening in Word and then adding line numbers in the document may help you in commenting line number 4404. Though it  may sound silly but I am adding the steps to add the line numbers  in word document too.

File -> Page Setup -> Layouts -> Click on line numbers --> continuous

Line no 4404

and the following one

if defined? ''.getbyte
      @encoding = "X"      # ruby 1.9.x or greater
      # @encoding_name = Encoding.default_external.to_s
   end

For details the following URLs are really helpful
http://trbhoang.blogspot.com/2010/05/issue-with-rspec-on-windows.html
http://tom.net.nz/2010/09/installing-diaspora-on-windows/