title: Ruby Passenger wont start
body: <p>I was tasked with upgrading the ruby installation on a machine the other day. I installed from source (typically ./configure, make, make install) and updated all gems. Currently, the site won't load with a Ruby Rack error, which I have no idea how to solve:</p>
  
  <pre><code>[ pid=21855 thr=104368260 file=utils.rb:176 time=2013-02-19 11:33:32.952 ]: *** Exception PhusionPassenger::UnknownError in PhusionPassenger::Rack::ApplicationSpawner (undefined method `&lt;&lt;' for nil:NilClass (NoMethodError)) (process 21855, thread #&lt;Thread:0x0000000c711108&gt;):
          from /usr/local/lib/ruby/gems/1.9.1/gems/rack-flash-0.1.2/lib/rack/flash.rb:20:in `run'
          from config.ru:7:in `block in &lt;main&gt;'
          from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
          from /usr/local/lib/ruby/gems/1.9.1/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
          from config.ru:1:in `new'
          from config.ru:1:in `&lt;main&gt;'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/rack/application_spawner.rb:225:in `eval'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/rack/application_spawner.rb:225:in `load_rack_app'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/rack/application_spawner.rb:157:in `block in initialize_server'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/utils.rb:563:in `report_app_init_status'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/rack/application_spawner.rb:154:in `initialize_server'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server.rb:204:in `start_synchronously'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server.rb:180:in `start'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/rack/application_spawner.rb:129:in `start'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/spawn_manager.rb:253:in `block (2 levels) in spawn_rack_application'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/spawn_manager.rb:246:in `block in spawn_rack_application'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize'
          from &lt;internal:prelude&gt;:10:in `synchronize'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/spawn_manager.rb:244:in `spawn_rack_application'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/spawn_manager.rb:137:in `spawn_application'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
          from /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.19/helper-scripts/passenger-spawn-server:99:in `&lt;main&gt;'
  </code></pre>
  
  <p>Have any of you seen this type of error before? Any thoughts on how to solve it?</p>