Can't start new application RoR, using Cygwin on Windows - ruby-on-rails-3

Question

I've been following this tutorial. When i started the new app in chapter 3 i came across and issue with gem json. i thought i should abbandon the app and start again. Now i can't even start a new app. Here's the error i get.
$ rails new sample_app2
/usr/lib/ruby/site_ruby/1.8/rubygems/dependency.rb:247:in `to_specs': Could not find json (~> 1.4) amongst [actionmailer-3.2.2, actionpack-3.2.2, activemodel-3.2.2, activerecord-3.2.2, activeresource-3.2.2, activesupport-3.2.2, addressable-2.2.7, arel-3.0.2, builder-3.0.0, bundler-1.1.3, bundler-1.1.2, coffee-rails-3.2.2, coffee-script-2.2.0, coffee-script-source-1.2.0, diff-lcs-1.1.3, erubis-2.7.0, execjs-1.3.0, heroku-2.22.0, heroku-2.21.3, hike-1.2.1, i18n-0.6.0, journey-1.0.3, jquery-rails-2.0.1, json_pure-1.6.6, launchy-2.1.0, mail-2.4.4, mime-types-1.18, multi_json-1.2.0, multi_json-1.1.0, netrc-0.7.1, polyglot-0.3.3, rack-1.4.1, rack-cache-1.2, rack-ssl-1.3.2, rack-test-0.6.1, rails-3.2.2, railties-3.2.2, rake-0.9.2.2, rdoc-3.12, rest-client-1.6.7, rspec-2.9.0, rspec-core-2.9.0, rspec-expectations-2.9.0, rspec-mocks-2.9.0, rspec-rails-2.9.0, rubyzip-0.9.6.1, sass-3.1.15, sass-rails-3.2.5, sprockets-2.3.1, sprockets-2.1.2, sqlite3-1.3.5, sqlite3-ruby-1.3.3, thor-0.14.6, tilt-1.3.3, treetop-1.4.10, tzinfo-0.3.32, uglifier-1.2.3] (Gem::LoadError)
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:772:in `activate_dependencies'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:761:in `each'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:761:in `activate_dependencies'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:745:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:775:in `activate_dependencies'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:761:in `each'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:761:in `activate_dependencies'
from /usr/lib/ruby/site_ruby/1.8/rubygems/specification.rb:745:in `activate'
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:1211:in `gem'
from /usr/bin/rails:18
I've noticed previous recommendations to install DevKit, but I'm not sure if that is the right move with Cygwin???

Answer 1

Ruby installer worked so much better for me. Cygwin just provided so many problems. It may have been mainly user error, but everywhere I turned I ran into brick walls.
Here's a great tutorial (with downloads) on installing Ruby on Rails including sqlite, bundler, git and devkit
http://railsinstaller.org/