After installing Redmine 2.x I got this error:
*** Exception PhusionPassenger::UnknownError in PhusionPassenger::Rack::ApplicationSpawner (Could not find rake-0.9.2.2 in any of the sources (Bundler::GemNotFound)) (process 16175): from /var/lib/gems/1.8/gems/bundler-1.1.5/lib/bundler/spec_set.rb:90:in `materialize' from /var/lib/gems/1.8/gems/bundler-1.1.5/lib/bundler/spec_set.rb:83:in `map!' from /var/lib/gems/1.8/gems/bundler-1.1.5/lib/bundler/spec_set.rb:83:in `materialize' from /var/lib/gems/1.8/gems/bundler-1.1.5/lib/bundler/definition.rb:127:in `specs'
To solve this I run this command in the redmine application directory
/var/www/redmine/bundle install --path vendor/bundle