Wenn ich versuche, die 'Bundle-Installation' auszuführen, erhalte ich einen seltsamen Fehler: "Ungültige Byte-Sequenz in US-ASCII (ArgumentError)"

  $ bundle install
    Updating git://github.com/devton/catarse_paypal_express.git
    Unfortunately, a fatal error has occurred. Please see the Bundler
    troubleshooting documentation at http://bit.ly/bundler-issues. Thanks!
    /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler.rb:294:in `block in load_gemspec_uncached': invalid byte sequence in US-ASCII (ArgumentError)
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler.rb:291:in `chdir'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler.rb:291:in `load_gemspec_uncached'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler.rb:282:in `load_gemspec'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:411:in `block in load_spec_files'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:410:in `each'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:410:in `load_spec_files'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:799:in `load_spec_files'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:381:in `local_specs'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/source.rb:774:in `specs'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:491:in `block in converge_locked_specs'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:480:in `each'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:480:in `converge_locked_specs'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:166:in `resolve'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:113:in `specs'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/definition.rb:108:in `resolve_remotely!'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/installer.rb:81:in `run'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/installer.rb:14:in `install'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/cli.rb:230:in `install'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/vendor/thor/task.rb:27:in `run'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/vendor/thor/invocation.rb:120:in `invoke_task'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/vendor/thor.rb:275:in `dispatch'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/vendor/thor/base.rb:408:in `start'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/bin/bundle:14:in `block in <top (required)>'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/lib/bundler/friendly_errors.rb:4:in `with_friendly_errors'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/gems/bundler-1.2.3/bin/bundle:14:in `<top (required)>'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/bin/bundle:19:in `load'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/bin/bundle:19:in `<main>'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/bin/ruby_noexec_wrapper:14:in `eval'
        from /Users/.../.rvm/gems/ruby-1.9.2-p320@global/bin/ruby_noexec_wrapper:14:in `<main>'

Ich habe diese Problemumgehung gefunden (die für mich funktioniert):

if RUBY_VERSION =~ /1.9/
  Encoding.default_external = Encoding::UTF_8
  Encoding.default_internal = Encoding::UTF_8
end

Aber ich denke, dass es später einen anderen Fehler verursacht, also würde ich ihn lieber nicht verwenden und einfach versuchen, zu verstehen, was hier wirklich falsch ist. Ich weiß mit Sicherheit, dass derselbe Code auf einem anderen System funktioniert ...