title: Error "uninitialized constant Rails::Engine (NameError)"
body: <p>I am trying to join a Rails project. This project uses rails 2.3.8 and Ruby 1.8.7 so I am using RVM. I am also using gem v1.3.7</p>
  
  <p>When I fire up the server, everything is ok. But then, when I try to access it through my browser, it crashes and I get the following trace:</p>
  
  <pre><code>/Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:440:in `load_missing_constant': uninitialized constant Rails::Engine (NameError)
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:80:in `const_missing'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/devise_invitable-0.3.6/lib/devise_invitable/rails.rb:2
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:521:in `new_constants_in'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/devise_invitable-0.3.6/lib/devise_invitable.rb:16
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:521:in `new_constants_in'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/rails/gem_dependency.rb:215:in `load'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:307:in `load_gems'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:307:in `each'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:307:in `load_gems'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:169:in `process'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:113:in `send'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/initializer.rb:113:in `run'
          from /Users/ca/Documents/Project/Sources/Project-test/config/environment.rb:9
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:521:in `new_constants_in'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:156:in `require'
          from /Users/ca/.rvm/gems/ruby-1.8.7-p334/gems/rails-2.3.8/lib/commands/server.rb:84
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
          from /Users/ca/.rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
          from ./script/server:3
  </code></pre>
  
  <p>Here are my installed gems:</p>
  
  <pre><code>actionmailer (2.3.8)
  actionpack (2.3.8)
  activemodel (3.0.5)
  activerecord (2.3.8)
  activeresource (2.3.8)
  activesupport (3.0.5, 2.3.8)
  addressable (2.2.4)
  arel (2.0.9)
  aws (2.4.4)
  aws-s3 (0.6.2)
  bcrypt-ruby (2.1.4)
  builder (3.0.0, 2.1.2)
  client_side_validations (2.9.9)
  crack (0.1.8)
  daemons (1.1.0)
  dalli (1.0.2)
  delayed_job (2.0.3)
  devise (1.1.7)
  devise_invitable (0.3.6)
  faraday (0.5.7, 0.4.6)
  fb_graph (1.5.3)
  googlecharts (1.6.1)
  http_connection (1.4.0)
  httparty (0.7.4)
  i18n (0.5.0)
  json (1.5.1, 1.4.3)
  mime-types (1.16)
  multi_json (0.0.5)
  multipart-post (1.1.0)
  net-ldap (0.1.1)
  nokogiri (1.4.4)
  oa-basic (0.1.5)
  oa-core (0.1.5)
  oa-enterprise (0.1.5)
  oa-oauth (0.1.5)
  oa-openid (0.1.5)
  oauth (0.4.4)
  oauth2 (0.1.1, 0.0.13)
  omniauth (0.1.5)
  paperclip (2.3.8)
  pyu-ruby-sasl (0.0.3.2)
  rack (1.1.1)
  rack-openid (1.1.2)
  rails (2.3.8)
  rake (0.8.7)
  RedCloth (4.2.7)
  rest-client (1.6.1)
  ruby-openid (2.1.8)
  ruby-openid-apps-discovery (1.2.0)
  rubygems-update (1.3.7)
  rubyntlm (0.1.1)
  tzinfo (0.3.24)
  uuidtools (2.1.2)
  validates_timeliness (2.3.0)
  validation_reflection (0.3.7)
  validation_reflection-active_model (0.3.1)
  warden (1.0.3)
  will_paginate (2.3.15)
  xml-simple (1.0.14)
  </code></pre>
  
  <p>Where does the problem come from?</p>
  
  <p>Thank you very much for your help!</p>