I've just had the same issue. It's probably because avahi daemon is not active (In my setup, it's disabled in /etc/default/avahi-daemon).
-- [apport] avahi-discover crashed with DBusException in __call__() https://launchpad.net/bugs/85692 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
