How to start server?

[MR]

when i run rails s then following error occurs "No such file or directory - /usr/lib/ruby/vendor_ruby/rails or s/vendor/rails"

create  
  create  app/controllers
  create  app/helpers
  create  app/models
  create  app/views/layouts
  create  config/environments
  create  config/initializers
  create  config/locales
  create  db
  create  doc
  create  lib
  create  lib/tasks
  create  log
  create  public/images
  create  public/javascripts
  create  public/stylesheets
  create  script/performance
  create  test/fixtures
  create  test/functional
  create  test/integration
  create  test/performance
  create  test/unit
  create  vendor
  create  vendor/plugins
  create  tmp/sessions
  create  tmp/sockets
  create  tmp/cache
  create  tmp/pids
  create  Rakefile
  create  README
  create  app/controllers/application_controller.rb
  create  app/helpers/application_helper.rb
  create  config/database.yml
  create  config/routes.rb
  create  config/locales/en.yml
  create  db/seeds.rb
  create  config/initializers/backtrace_silencers.rb
  create  config/initializers/inflections.rb
  create  config/initializers/mime_types.rb
  create  config/initializers/new_rails_defaults.rb
  create  config/initializers/session_store.rb
  create  config/initializers/cookie_verification_secret.rb
  create  config/environment.rb
  create  config/boot.rb
  create  config/environments/production.rb
  create  config/environments/development.rb
  create  config/environments/test.rb
  create  script/about
  create  script/console
  create  script/dbconsole
  create  script/destroy
  create  script/generate
  create  script/runner
  create  script/server
  create  script/plugin
  create  script/performance/benchmarker
  create  script/performance/profiler
  create  test/test_helper.rb
  create  test/performance/browsing_test.rb
  create  public/404.html
  create  public/422.html
  create  public/500.html
  create  public/index.html
  create  public/favicon.ico
  create  public/robots.txt
  create  public/images/rails.png
  create  public/javascripts/prototype.js
  create  public/javascripts/effects.js
  create  public/javascripts/dragdrop.js
  create  public/javascripts/controls.js
  create  public/javascripts/application.js
  create  doc/README_FOR_APP
  create  log/server.log
  create  log/production.log
  create  log/development.log
  create  log/test.log
  create  vendor/rails

No such file or directory - /usr/lib/ruby/vendor_ruby/rails or s/vendor/rails