Running the samples on a linux box running ubuntu 12.10 (64 bit), I can register the service but the browse.rb script doesn't list it successfully. This works fine on a Mac. Tried it on two different ubuntu machines (both running 12.10) with the same failure mode. It just never lists any services as found.
I can give any more details needed. Not sure if this is a bug with libavahi's compat lib or what. Browsing from avahi-discover works fine.