The contributed packages found in this directory (/pub/Owl/contrib/2.0)
are intended for use on Owl 2.0-stable (or 2.0-release, but you'd want
to keep yours updated to 2.0-stable anyway). They may not install/work
on Owl-current, as well as on other versions of Owl. See:

http://www.openwall.com/lists/owl-users/2009/09/28/2
http://openwall.info/wiki/Owl/packages