`assert_index': No such middleware to insert before: "Rack::Sendfile"

Question

When cloning my repository, which works from the directory I am developing it in, I'm getting an error. The weird part is that it uses the same version of Ruby and the same Gemset, but I get the feeling that this error still comes from an error with Gems. Anyone got an idea what could be causing it? There are my gems:

source 'https://rubygems.org'

gem 'rails', '3.2.2'
gem 'mysql2'
gem 'activeadmin'

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

gem 'jquery-rails'

The error is as follows:

eml/orchid → master rails s
=> Booting WEBrick
=> Rails 3.2.2 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/actionpack-3.2.2/lib/action_dispatch/middleware/stack.rb:120:in `assert_index': No such middleware to insert before: "Rack::Sendfile" (RuntimeError)
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/actionpack-3.2.2/lib/action_dispatch/middleware/stack.rb:83:in `insert'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/configuration.rb:38:in `block in merge_into'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/configuration.rb:37:in `each'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/configuration.rb:37:in `merge_into'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/engine.rb:469:in `app'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/application/finisher.rb:31:in `block in <module:Finisher>'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `instance_exec'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `run'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/initializable.rb:55:in `block in run_initializers'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `each'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `run_initializers'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/application.rb:136:in `initialize!'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /Users/eml/Projects/orchid/orchid/config/environment.rb:5:in `<top (required)>'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `block in require'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
    from /Users/eml/Projects/orchid/orchid/config.ru:4:in `block in <main>'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
    from /Users/eml/Projects/orchid/orchid/config.ru:1:in `new'
    from /Users/eml/Projects/orchid/orchid/config.ru:1:in `<main>'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/builder.rb:40:in `eval'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/builder.rb:40:in `parse_file'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/server.rb:200:in `app'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/commands/server.rb:46:in `app'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/server.rb:301:in `wrapped_app'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/rack-1.4.1/lib/rack/server.rb:252:in `start'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/commands/server.rb:70:in `start'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/commands.rb:55:in `block in <top (required)>'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/commands.rb:50:in `tap'
    from /Users/eml/.rvm/gems/ruby-1.9.3-p125@LampPostDb/gems/railties-3.2.2/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

Thank you!

UPDATE: Screwed it up so no it doesn't work in the initial directory either. Definitely related to some gem.

UPDATE2: Created a new gemset through RVM and ran bundle install, here's a rundown of the gems and their versions installed:

eml/LampPostDb → master rvm --rvmrc --create 1.9.3-p125@railsadmin
eml/LampPostDb → master bundle install
Fetching source index for https://rubygems.org/
Installing rake (0.9.2.2) 
Installing i18n (0.6.0) 
Installing multi_json (1.1.0) 
Installing activesupport (3.2.2) 
Installing builder (3.0.0) 
Installing activemodel (3.2.2) 
Installing erubis (2.7.0) 
Installing journey (1.0.3) 
Installing rack (1.4.1) 
Installing rack-cache (1.2) 
Installing rack-test (0.6.1) 
Installing hike (1.2.1) 
Installing tilt (1.3.3) 
Installing sprockets (2.1.2) 
Installing actionpack (3.2.2) 
Installing mime-types (1.18) 
Installing polyglot (0.3.3) 
Installing treetop (1.4.10) 
Installing mail (2.4.4) 
Installing actionmailer (3.2.2) 
Installing sass (3.1.15) 
Installing bourbon (1.4.0) 
Installing bcrypt-ruby (3.0.1) with native extensions 
Installing orm_adapter (0.0.6) 
Installing rack-ssl (1.3.2) 
Installing json (1.6.5) with native extensions 
Installing rdoc (3.12) 
Installing thor (0.14.6) 
Installing railties (3.2.2) 
Installing warden (1.1.1) 
Installing devise (2.0.4) 
Installing fastercsv (1.5.4) 
Installing formtastic (2.1.1) 
Installing has_scope (0.5.1) 
Installing responders (0.9.0) 
Installing inherited_resources (1.3.1) 
Installing jquery-rails (2.0.1) 
Installing kaminari (0.13.0) 
Installing arel (3.0.2) 
Installing tzinfo (0.3.32) 
Installing activerecord (3.2.2) 
Installing polyamorous (0.5.0) 
Installing meta_search (1.1.3) 
Installing activeresource (3.2.2) 
Using bundler (1.0.21) 
Installing rails (3.2.2) 
Installing activeadmin (0.4.3) 
Installing coffee-script-source (1.2.0) 
Installing execjs (1.3.0) 
Installing coffee-script (2.2.0) 
Installing coffee-rails (3.2.2) 
Installing mysql2 (0.3.11) with native extensions 
Installing sass-rails (3.2.5) 
Installing uglifier (1.2.3) 

Answer 1

Of course I find the culprit after asking the question. Initially I had had found an issue on Github describing a simlar problem, but I had no compass.rb initializer. What I didn't figure out was that I have a sass.rb initializer, which contains pretty much the same lines of code.

I'm not entirely sure if commenting this whole file out is okay, or if it's going to cause a bunch of problems. The app starts fine now, but the future can only tell.

If someone has a better answer than this I'll happily mark theirs as correct.