bundler/capistrano deployment - Rails3 / bundler 1.0.15

deploying an app with bundler/capistrano recipe, I get the following
warnings

WARNING: abstract-1.0.0 has an invalid nil value for @cert_chain
WARNING: builder-2.1.2 has an invalid nil value for @cert_chain
WARNING: rubyntlm-0.1.1 has an invalid nil value for @cert_chain
WARNING: ya2yaml-0.30 has an invalid nil value for @cert_chain

@cert_chain; what does it means ? is it important ?

This is a warning generated by RubyGems as it installs each of these
gems. It just means that the gem's specification isn't following the
rules that RubyGems expects. Recent versions of RubyGems have been
more vocal about reporting these warnings.

However, this isn't going to affect the running of your gems, so I
wouldn't worry about it. The warnings will go away once the
maintainers of those gems update them to fix the error in their
specification.

Chris