Not crazy at all 😉
Im running edgy on my desktop, Win XP on my notebook, and uNSLUng 6.8 on my Slug (linksys nslu2) – all run firefly, various versions, but serving up nice.
Right, so your Linux may be the culprit. Getting closer. Are you using iptables to block any multicast traffic? IE any linux firewall?
Blocking multicasts seems to be quite common these days. Also, is your avahi-daemon started? firefly likes to use avahi in ubuntu 😉
And without that daemon it doesnt advertise itself in the network.