undefined local variable or method `version_requirements'

undefined local variable or method `version_requirements' for #<Rails::GemDependency:0x1022cc1c8> (NameError)

uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)

$ gem install rubygems-update -v='1.4.2'
$ gem uninstall rubygems-update -v='1.5.0'
$ update_rubygems

gem update --system=1.4.2