Can't read ionicframework documentation in offline mode

Hi community,
I’m trying to read the documentation in offline mode, but i’m facing some difficulties.
I have installed jekyll with all its dependencies.
I’m located into ionic-site path and then i executed those commands like in the picture,but i got errors:

Liquid Exception: undefined method `sub' for nil:NilClass in _posts/2013-12-18-ionic-and-nitrousio.markdown

After adding --trace :

/Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/tags/highlight.rb:77:in `add_code_tags': undefined method `sub' for nil:NilClass (NoMethodError)
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/tags/highlight.rb:56:in `render_pygments'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/tags/highlight.rb:45:in `render'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/block.rb:106:in `block in render_all'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/block.rb:93:in `each'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/block.rb:93:in `render_all'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/block.rb:82:in `render'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/template.rb:124:in `render'
from /Library/Ruby/Gems/2.0.0/gems/liquid-2.5.5/lib/liquid/template.rb:132:in `render!'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/convertible.rb:88:in `render_liquid'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/convertible.rb:150:in `do_layout'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/post.rb:259:in `render'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/site.rb:239:in `block in render'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/site.rb:238:in `each'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/site.rb:238:in `render'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/site.rb:39:in `process'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/command.rb:18:in `process_site'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/commands/build.rb:23:in `build'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/lib/jekyll/commands/build.rb:7:in `process'
from /Library/Ruby/Gems/2.0.0/gems/jekyll-1.4.3/bin/jekyll:97:in `block (2 levels) in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/command.rb:180:in `call'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/command.rb:180:in `call'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/command.rb:155:in `run'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/runner.rb:422:in `run_active_command'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/runner.rb:82:in `run!'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/delegates.rb:8:in `run!'
from /Library/Ruby/Gems/2.0.0/gems/commander-4.1.6/lib/commander/import.rb:10:in `block in <top (required)>'

Huh, strange. We are not using any custom plugins or anything (they don’t work on GitHub). Perhaps try ruby 1.9.3?

Same, couldn’t get this to work either.