Using Unicorn, Rails is trying to compile the assets even though the assets themselves are alredy precompiled.

application.rb

require File.expand_path('../boot', __FILE__)

require 'rails/all'
require 'exception_notifier'

if defined?(Bundler)
  # Bundler.require(:default, :assets, Rails.env)
  Bundler.require *Rails.groups(:assets => %w(development test))
end
module Tarifador
  class Application < Rails::Application
    config.generators do |g|
      g.stylesheets false
    end
    stylesheets_directory = "#{Rails.root}/app/assets/stylesheets"
    config.assets.precompile << /(^[^_]|\/[^_])[^\/]*/

      # Settings in config/environments/* take precedence over those specified here.
      # Application configuration should go into files in config/initializers
      # -- all .rb files in that directory are automatically loaded.

      # Custom directories with classes and modules you want to be autoloadable.
      # config.autoload_paths += %W(#{config.root}/extras)

      # enumerations
      config.autoload_paths += Dir[Rails.root.join('app', 'models', '{**}')]
    config.autoload_paths += %W(#{config.root}/app/models/enumerations)
    config.autoload_paths += Dir[Rails.root.join('lib')]
    config.autoload_paths += Dir[Rails.root.join('lib/form_builders')]
    config.autoload_paths += %W(#{config.root}/lib/rails_ext/view)

    # Only load the plugins named here, in the order given (default is alphabetical).
    # :all can be used as a placeholder for all plugins not explicitly named.
    # config.plugins = [ :exception_notification, :ssl_requirement, :all ]

    # Activate observers that should always be running.
    # config.active_record.observers = :cacher, :garbage_collector, :forum_observer

    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
    # config.time_zone = 'Central Time (US & Canada)'

    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
    # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
    config.i18n.default_locale = :"pt-BR"

    # Configure the default encoding used in templates for Ruby 1.9.
    config.encoding = "utf-8"

    config.use_cdn_for_javascript = true
    config.show_devise_errors_at_login = true
    config.assets.enabled = true

    # Configure sensitive parameters which will be filtered from the log file.
    config.filter_parameters += [:password, :password_confirmation]

    config.action_mailer.raise_delivery_errors = true
  end
end

staging.rb

Tarifador::Application.configure do
  # Settings specified here will take precedence over those in config/application.rb

  # The production environment is meant for finished, "live" apps.
  # Code is not reloaded between requests
  config.cache_classes = true

  # Full error reports are disabled and caching is turned on
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true

  # Specifies the header that your server uses for sending files
  config.action_dispatch.x_sendfile_header = "X-Sendfile"

  config.assets.js_compressor  = :uglifier

  config.assets.digest = true
  # For nginx:
  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'

  # If you have no front-end server that supports something like X-Sendfile,
  # just comment this out and Rails will serve the files

  # See everything in the log (default is :info)
  # config.log_level = :debug

  # Use a different logger for distributed setups
  # config.logger = SyslogLogger.new

  # Use a different cache store in production
  # config.cache_store = :mem_cache_store

  # Disable Rails's static asset server
  # In production, Apache or nginx will already do this
  config.serve_static_assets = false
  config.assets.compress = true

  # Enable serving of images, stylesheets, and javascripts from an asset server
  # config.action_controller.asset_host = "http://assets.example.com"

  # Disable delivery errors, bad email addresses will be ignored
  # config.action_mailer.raise_delivery_errors = false

  # Enable threaded mode
  # config.threadsafe!

  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
  # the I18n.default_locale when a translation can not be found)
  config.i18n.fallbacks = true

  # Send deprecation notices to registered listeners
  config.active_support.deprecation = :notify
end