Предупреждение Rake «уже инициализированная константа WFKV_»

Пытаюсь запустить rake cucumber: ok и получаю эта ошибка:

/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rack-1.3.4/lib/rack/backports/uri/common_192. rb: 53: предупреждение: уже инициализированная константа WFKV_

Затем:
Команда завершилась неудачно со статусом (1): [/Users/dev/.rbenv/versions/1.9.2-p290/bin...

Я новичок в Rails, и Google ничего не обнаружил для этой ошибки.

РЕДАКТИРОВАТЬ: Я пробовал добавить bundle exec , и это не имеет значения.

Вот что у меня получилось с - trace :

/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/file_utils.rb:53:in `block in create_shell_runner'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/file_utils.rb:45:in `call'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/file_utils.rb:45:in `sh'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/file_utils_ext.rb:36:in `sh'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/cucumber-1.1.0/lib/cucumber/rake/task.rb:104:in `run'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/cucumber-1.1.0/lib/cucumber/rake/task.rb:193:in `block in define_task'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:205:in `call'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:200:in `each'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:112:in `invoke_task'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:90:in `block (2 levels) in top_level'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:90:in `each'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:90:in `block in top_level'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:84:in `top_level'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:62:in `block in run'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/lib/rake/application.rb:59:in `run'
/Users/dev/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/rake-0.9.2/bin/rake:32:in `<top (required)>'
/Users/dev/.rbenv/versions/1.9.2-p290/bin/rake:19:in `load'
/Users/dev/.rbenv/versions/1.9.2-p290/bin/rake:19:in `<main>'
Tasks: TOP => cucumber:ok