我一直在努力让twitter-bootstrap-rails gem在我的windows机器上工作，在尝试安装'therubyracer' gem时遇到了一个错误，这是一个依赖于旧版本的less gem的错误。
我想升级到更少的2.2.1，这是不依赖于ubyracer，但尽管如此，它似乎认为我仍然需要安装ubyracer。以下是我得到的错误输出，当我试图启动我的Rails服务器'rails s'。

$ rails s
[WARNING] Please install gem 'therubyracer' to use Less.
c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require': cannot load such file -- v8 (LoadError)
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less/java_script/v8_context.rb:2:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less/java_script.rb:9:in `default_context_wrapper'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less/java_script.rb:17:in `context_wrapper'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less/loader.rb:10:in `initialize'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less.rb:14:in `new'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less.rb:14:in `<module:Less>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-2.2.2/lib/less.rb:9:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-rails-2.2.3/lib/less/rails.rb:6:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/less-rails-2.2.3/lib/less-rails.rb:1:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:236:in `load_dependency'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/activesupport-3.2.8/lib/active_support/dependencies.rb:251:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/twitter-bootstrap-rails-2.1.2/lib/twitter-bootstrap-rails.rb:9:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:68:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:66:in `each'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:66:in `block in require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:55:in `each'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runtime.rb:55:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler.rb:122:in `require'
    from C:/Sites/alliance/config/application.rb:9:in `<top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:53:in `require'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:53:in `block in <top (required)>'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:50:in `tap'
    from c:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/railties-3.2.8/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

这里是我的Gemfile和Gemfile.lock文件。有人能帮我弄清楚如何告诉我的应用程序它不需要安装“therubyracer”吗？

• --- Gemfile ----

source 'https://rubygems.org'

gem 'rails',   '~> 3.2.3'
gem 'jquery-rails'
gem 'haml-rails'
gem 'simple_form'
gem 'decent_exposure'
gem "devise", :git => "git://github.com/plataformatec/devise.git"
gem 'cancan'
gem 'prawn'
gem 'ransack'
gem 'eventmachine', '= 1.0.0.rc.4'
gem 'therubyracer', :platforms => :ruby

group :assets do
  gem 'execjs'
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'
  gem 'bootstrap-sass'
  gem 'twitter-bootstrap-rails' 
  gem 'uglifier', '>= 1.0.3'
end

group :development, :test do
  gem 'debugger'
  gem 'rails_best_practices'
  gem 'factory_girl_rails', '~> 2.0'
  gem 'sqlite3'
  gem 'simplecov', require: false
  gem 'rspec-rails'
  gem 'rspec-instafail'
  gem 'rspec-steps'
  gem 'factory_girl_rails', '~> 2.0'
  gem "capybara"
  gem "selenium-webdriver"
  gem 'launchy' # provides save_and_open_page
  gem 'fuubar'

  gem 'database_cleaner'
  gem 'rantly'
  gem 'heroku'
  gem 'rb-fsevent' #, :require => false if RUBY_PLATFORM =~ /darwin/i
  gem 'guard-rspec'
end

group :production do
  gem 'mysql2'
  gem 'thin'
  gem 'pg'
end

---- Gemfile.lock ----

GIT
  remote: git://github.com/plataformatec/devise.git
  revision: f7dd59839cd39ed3c57948d37e8a95c697c14647
  specs:
    devise (2.1.2)
      bcrypt-ruby (~> 3.0)
      orm_adapter (~> 0.1)
      railties (~> 3.1)
      warden (~> 1.2.1)

GEM
  remote: https://rubygems.org/
  specs:
    Ascii85 (1.0.1)
    actionmailer (3.2.8)
      actionpack (= 3.2.8)
      mail (~> 2.4.4)
    actionpack (3.2.8)
      activemodel (= 3.2.8)
      activesupport (= 3.2.8)
      builder (~> 3.0.0)
      erubis (~> 2.7.0)
      journey (~> 1.0.4)
      rack (~> 1.4.0)
      rack-cache (~> 1.2)
      rack-test (~> 0.6.1)
      sprockets (~> 2.1.3)
    activemodel (3.2.8)
      activesupport (= 3.2.8)
      builder (~> 3.0.0)
    activerecord (3.2.8)
      activemodel (= 3.2.8)
      activesupport (= 3.2.8)
      arel (~> 3.0.2)
      tzinfo (~> 0.3.29)
    activeresource (3.2.8)
      activemodel (= 3.2.8)
      activesupport (= 3.2.8)
    activesupport (3.2.8)
      i18n (~> 0.6)
      multi_json (~> 1.0)
    addressable (2.3.2)
    arel (3.0.2)
    awesome_print (1.0.2)
    bcrypt-ruby (3.0.1-x86-mingw32)
    bootstrap-sass (2.1.0.0)
    builder (3.0.1)
    cancan (1.6.8)
    capybara (1.1.2)
      mime-types (>= 1.16)
      nokogiri (>= 1.3.3)
      rack (>= 1.0.0)
      rack-test (>= 0.5.4)
      selenium-webdriver (~> 2.0)
      xpath (~> 0.1.4)
    childprocess (0.3.5)
      ffi (~> 1.0, >= 1.0.6)
    coffee-rails (3.2.2)
      coffee-script (>= 2.2.0)
      railties (~> 3.2.0)
    coffee-script (2.2.0)
      coffee-script-source
      execjs
    coffee-script-source (1.3.3)
    colored (1.2)
    columnize (0.3.6)
    commonjs (0.2.6)
    daemons (1.1.9)
    database_cleaner (0.8.0)
    debugger (1.2.0)
      columnize (>= 0.3.1)
      debugger-linecache (~> 1.1.1)
      debugger-ruby_core_source (~> 1.1.3)
    debugger-linecache (1.1.2)
      debugger-ruby_core_source (>= 1.1.1)
    debugger-ruby_core_source (1.1.3)
    decent_exposure (1.0.2)
    diff-lcs (1.1.3)
    erubis (2.7.0)
    eventmachine (1.0.0.rc.4-x86-mingw32)
    excon (0.16.2)
    execjs (1.4.0)
      multi_json (~> 1.0)
    factory_girl (3.0.0)
      activesupport (>= 3.0.0)
    factory_girl_rails (2.0.0)
      factory_girl (~> 3.0.0)
      railties (>= 3.0.0)
    ffi (1.1.5)
    fuubar (1.0.0)
      rspec (~> 2.0)
      rspec-instafail (~> 0.2.0)
      ruby-progressbar (~> 0.0.10)
    guard (1.3.2)
      listen (>= 0.4.2)
      thor (>= 0.14.6)
    guard-rspec (1.2.1)
      guard (>= 1.1)
    haml (3.1.7)
    haml-rails (0.3.4)
      actionpack (~> 3.0)
      activesupport (~> 3.0)
      haml (~> 3.0)
      railties (~> 3.0)
    hashery (2.0.1)
    heroku (2.31.2)
      heroku-api (~> 0.3.4)
      launchy (>= 0.3.2)
      netrc (~> 0.7.7)
      rest-client (~> 1.6.1)
      rubyzip
    heroku-api (0.3.4)
      excon (~> 0.16.1)
    hike (1.2.1)
    i18n (0.6.1)
    journey (1.0.4)
    jquery-rails (2.1.2)
      railties (>= 3.1.0, < 5.0)
      thor (~> 0.14)
    json (1.7.5)
    launchy (2.1.2)
      addressable (~> 2.3)
    less (2.2.2)
      commonjs (~> 0.2.6)
    less-rails (2.2.3)
      actionpack (>= 3.1)
      less (~> 2.2.0)
    libwebsocket (0.1.5)
      addressable
    listen (0.5.0)
    mail (2.4.4)
      i18n (>= 0.4.0)
      mime-types (~> 1.16)
      treetop (~> 1.4.8)
    mime-types (1.19)
    multi_json (1.3.6)
    mysql2 (0.3.11-x86-mingw32)
    netrc (0.7.7)
    nokogiri (1.5.5-x86-mingw32)
    orm_adapter (0.4.0)
    pdf-reader (1.2.0)
      Ascii85 (~> 1.0.0)
      hashery (~> 2.0)
      ruby-rc4
    pg (0.14.1-x86-mingw32)
    polyamorous (0.5.0)
      activerecord (~> 3.0)
    polyglot (0.3.3)
    prawn (0.12.0)
      pdf-reader (>= 0.9.0)
      ttfunk (~> 1.0.2)
    progressbar (0.11.0)
    rack (1.4.1)
    rack-cache (1.2)
      rack (>= 0.4)
    rack-ssl (1.3.2)
      rack
    rack-test (0.6.1)
      rack (>= 1.0)
    rails (3.2.8)
      actionmailer (= 3.2.8)
      actionpack (= 3.2.8)
      activerecord (= 3.2.8)
      activeresource (= 3.2.8)
      activesupport (= 3.2.8)
      bundler (~> 1.0)
      railties (= 3.2.8)
    rails_best_practices (1.10.1)
      activesupport
      awesome_print
      colored
      erubis
      i18n
      progressbar
      sexp_processor
    railties (3.2.8)
      actionpack (= 3.2.8)
      activesupport (= 3.2.8)
      rack-ssl (~> 1.3.2)
      rake (>= 0.8.7)
      rdoc (~> 3.4)
      thor (>= 0.14.6, < 2.0)
    rake (0.9.2.2)
    ransack (0.7.0)
      actionpack (~> 3.0)
      activerecord (~> 3.0)
      polyamorous (~> 0.5.0)
    rantly (0.3.1)
    rb-fsevent (0.9.1)
    rdoc (3.12)
      json (~> 1.4)
    rest-client (1.6.7)
      mime-types (>= 1.16)
    rspec (2.11.0)
      rspec-core (~> 2.11.0)
      rspec-expectations (~> 2.11.0)
      rspec-mocks (~> 2.11.0)
    rspec-core (2.11.1)
    rspec-expectations (2.11.3)
      diff-lcs (~> 1.1.3)
    rspec-instafail (0.2.4)
    rspec-mocks (2.11.2)
    rspec-rails (2.11.0)
      actionpack (>= 3.0)
      activesupport (>= 3.0)
      railties (>= 3.0)
      rspec (~> 2.11.0)
    rspec-steps (0.0.8)
      rspec (>= 2.6)
    ruby-progressbar (0.0.10)
    ruby-rc4 (0.1.5)
    rubyzip (0.9.9)
    sass (3.2.1)
    sass-rails (3.2.5)
      railties (~> 3.2.0)
      sass (>= 3.1.10)
      tilt (~> 1.3)
    selenium-webdriver (2.25.0)
      childprocess (>= 0.2.5)
      libwebsocket (~> 0.1.3)
      multi_json (~> 1.0)
      rubyzip
    sexp_processor (4.0.1)
    simple_form (2.0.2)
      actionpack (~> 3.0)
      activemodel (~> 3.0)
    simplecov (0.6.4)
      multi_json (~> 1.0)
      simplecov-html (~> 0.5.3)
    simplecov-html (0.5.3)
    sprockets (2.1.3)
      hike (~> 1.2)
      rack (~> 1.0)
      tilt (~> 1.1, != 1.3.0)
    sqlite3 (1.3.6-x86-mingw32)
    thin (1.4.1)
      daemons (>= 1.0.9)
      eventmachine (>= 0.12.6)
      rack (>= 1.0.0)
    thor (0.16.0)
    tilt (1.3.3)
    treetop (1.4.10)
      polyglot
      polyglot (>= 0.3.1)
    ttfunk (1.0.3)
    twitter-bootstrap-rails (2.1.2)
      actionpack (>= 3.1)
      less-rails (~> 2.2.3)
      railties (>= 3.1)
    tzinfo (0.3.33)
    uglifier (1.3.0)
      execjs (>= 0.3.0)
      multi_json (~> 1.0, >= 1.0.2)
    warden (1.2.1)
      rack (>= 1.0)
    xpath (0.1.4)
      nokogiri (~> 1.3)

PLATFORMS
  x86-mingw32

DEPENDENCIES
  bootstrap-sass
  cancan
  capybara
  coffee-rails (~> 3.2.1)
  database_cleaner
  debugger
  decent_exposure
  devise!
  eventmachine (= 1.0.0.rc.4)
  execjs
  factory_girl_rails (~> 2.0)
  fuubar
  guard-rspec
  haml-rails
  heroku
  jquery-rails
  launchy
  mysql2
  pg
  prawn
  rails (~> 3.2.3)
  rails_best_practices
  ransack
  rantly
  rb-fsevent
  rspec-instafail
  rspec-rails
  rspec-steps
  sass-rails (~> 3.2.3)
  selenium-webdriver
  simple_form
  simplecov
  sqlite3
  therubyracer
  thin
  twitter-bootstrap-rails
  uglifier (>= 1.0.3)