i have the same issue(“Barrier is starting.” But not working.)
it says
*** WARNING *** The program 'barrier' called 'DNSServiceRegister()' which is not supported (or only supported partially) in the Apple Bonjour compatibility layer of Avahi.
*** WARNING *** Please fix your application to use the native API of Avahi!
*** WARNING *** For more information see http://0pointer.de/blog/projects/avahi-compat.html