chef/json_compat (LoadError)

[pborreli]

not sure what I've done wrong rake fails with this error :

$ bundle exec rake monigusto:install
Installing monigusto cookbooks in /home/xxx/monigusto/monigusto
/home/xxx/.rvm/gems/ruby-1.9.2-p320@monigusto/gems/librarian-0.0.4/lib/librarian/chef/manifest.rb:28:in `require': no such file to load -- chef/json_compat (LoadError)

[pborreli]

tried to install again from a new box and had exact same issue