Eric-

There is a bug in ob-ruby --- if an literal 'hline is passed into
(e.g., :hline no) a ruby block, the execution fails due to an
incorrect datatype (this is not an issue in any other language). The
patch provided in
http://lists.gnu.org/archive/html/emacs-orgmode/2013-08/msg00316.html
(and reattached here), applies the solution used in ox-python to
handle the issue. An alternative solution is ok too :).

I would be glad to apply the patch myself, but since you are the owner
of the file i would appreciate you ok before proceeding.

tia,
rick