Ruby on rails 4 卡皮斯特拉诺部署。预编译的资产不起作用

我对应用程序部署有问题。在资产上部署崩溃：预编译。正如我所看到的，链轮存在问题。也许版本有问题，我必须把它锁定在某个特殊的版本上

Capistrano错误日志：

*** [err :: 188.166.2.53] rake aborted!
*** [err :: 188.166.2.53] NoMethodError: undefined method `directory?' for nil:NilClass
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:307:in `block in each_entry'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:303:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:303:in `each_entry'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:322:in `block in each_file'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:321:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:321:in `each_file'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:335:in `each_logical_path'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `to_a'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `compile'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-rails-2.1.3/lib/sprockets/rails/task.rb:61:in `block (3 levels) in define'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/rake/sprocketstask.rb:146:in `with_logger'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-rails-2.1.3/lib/sprockets/rails/task.rb:60:in `block (2 levels) in define'
*** [err :: 188.166.2.53] Tasks: TOP => assets:precompile
*** [err :: 188.166.2.53] (See full trace by running task with --trace)

gem 'rails', '4.1.0'
gem 'pg'
gem 'sass-rails', '~> 4.0.3'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.0.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0',          group: :doc
gem 'doorkeeper'
gem 'devise'
gem 'cancancan'
gem 'active_model_serializers'
gem 'therubyracer'
gem 'less-rails'
gem 'twitter-bootstrap-rails'
gem 'slim-rails'
gem 'ransack', github: 'activerecord-hackery/ransack', branch: 'rails-4.1'
gem 'quiet_assets', group: :development
gem 'carrierwave'
gem 'mini_magick'
gem 'kaminari'
gem 'nprogress-rails'
gem 'jquery_context_menu-rails'
gem 'jquery-turbolinks'
gem 'draper'
gem 'ancestry'
gem 'gretel'
gem 'rubocop', require: false

group :development do
  gem 'capistrano'
  gem 'rvm-capistrano'
  gem 'net-ssh', '2.7.0'
end

Gemfile:

*** [err :: 188.166.2.53] rake aborted!
*** [err :: 188.166.2.53] NoMethodError: undefined method `directory?' for nil:NilClass
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:307:in `block in each_entry'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:303:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:303:in `each_entry'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:322:in `block in each_file'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:321:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:321:in `each_file'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/base.rb:335:in `each_logical_path'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `each'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `to_a'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/sprockets/manifest.rb:115:in `compile'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-rails-2.1.3/lib/sprockets/rails/task.rb:61:in `block (3 levels) in define'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-2.11.0/lib/rake/sprocketstask.rb:146:in `with_logger'
*** [err :: 188.166.2.53] /home/deployer/.rvm/gems/ruby-2.1.1/ruby/2.1.0/gems/sprockets-rails-2.1.3/lib/sprockets/rails/task.rb:60:in `block (2 levels) in define'
*** [err :: 188.166.2.53] Tasks: TOP => assets:precompile
*** [err :: 188.166.2.53] (See full trace by running task with --trace)

gem 'rails', '4.1.0'
gem 'pg'
gem 'sass-rails', '~> 4.0.3'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.0.0'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0',          group: :doc
gem 'doorkeeper'
gem 'devise'
gem 'cancancan'
gem 'active_model_serializers'
gem 'therubyracer'
gem 'less-rails'
gem 'twitter-bootstrap-rails'
gem 'slim-rails'
gem 'ransack', github: 'activerecord-hackery/ransack', branch: 'rails-4.1'
gem 'quiet_assets', group: :development
gem 'carrierwave'
gem 'mini_magick'
gem 'kaminari'
gem 'nprogress-rails'
gem 'jquery_context_menu-rails'
gem 'jquery-turbolinks'
gem 'draper'
gem 'ancestry'
gem 'gretel'
gem 'rubocop', require: false

group :development do
  gem 'capistrano'
  gem 'rvm-capistrano'
  gem 'net-ssh', '2.7.0'
end

服务器： Ubuntu 14.04（2CPU，4GB）