y u no run jekyll?

gistfile1.txt

# warewolf@xasf:~/git/octopress$ rake generate
## Generating Site with Jekyll
About to run: compass compile --css-dir source/stylesheets
identical source/stylesheets/screen.css 
About to run: jekyll
Configuration from /home/warewolf/git/octopress/_config.yml
/home/warewolf/git/octopress/plugins/config_tag.rb:1:in `require': cannot load such file -- json (LoadError)
        from /home/warewolf/git/octopress/plugins/config_tag.rb:1:in `<top (required)>'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:78:in `require'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:78:in `block (2 levels) in setup'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:77:in `each'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:77:in `block in setup'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:76:in `each'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:76:in `setup'
        from /usr/local/share/gems/gems/jekyll-0.12.1/lib/jekyll/site.rb:31:in `initialize'
        from /usr/local/share/gems/gems/jekyll-0.12.1/bin/jekyll:238:in `new'
        from /usr/local/share/gems/gems/jekyll-0.12.1/bin/jekyll:238:in `<top (required)>'
        from /usr/local/bin/jekyll:23:in `load'
        from /usr/local/bin/jekyll:23:in `<main>'


# warewolf@xasf:~/git/octopress$ jekyll
Configuration from /home/warewolf/git/octopress/_config.yml
Building site: source -> public
Successfully generated site: source -> public
# warewolf@xasf:~/git/octopress$