当我使用middleman命令时，我收到错误

Question

当我使用midman命令时，我收到如下错误

# middleman
WARN: Unresolved specs during Gem::Specification.reset:
      thor (< 2.0, >= 0.15.2)
      json (>= 1.7.7, ~> 1.7)
WARN: Clearing out unresolved specs.
Please report a bug if this causes problems.
/usr/share/rubygems-integration/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:33:in `block in setup': You have already activated i18n 0.7.0, but your Gemfile requires i18n 0.6.9. Using bundle exec may solve this. (Gem::LoadError)
    from /usr/share/rubygems-integration/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:19:in `setup'
    from /usr/share/rubygems-integration/1.9.1/gems/bundler-1.3.5/lib/bundler.rb:120:in `setup'
    from /usr/share/rubygems-integration/1.9.1/gems/bundler-1.3.5/lib/bundler/setup.rb:7:in `<top (required)>'
    from /usr/local/lib/site_ruby/1.9.1/rubygems/core_ext/kernel_require.rb:69:in `require'
    from /usr/local/lib/site_ruby/1.9.1/rubygems/core_ext/kernel_require.rb:69:in `require'
    from /var/lib/gems/1.9.1/gems/middleman-core-3.3.10/lib/middleman-core/load_paths.rb:29:in `setup_load_paths'
    from /var/lib/gems/1.9.1/gems/middleman-core-3.3.10/bin/middleman:10:in `<top (required)>'
    from /usr/local/bin/middleman:23:in `load'
    from /usr/local/bin/middleman:23:in `<main>'

我也尝试过使用bundle exec middleman。