I updated my Mac Mini (Intel, OSX 10.4.9) to iTunes 7.1.1 just now, up from 7.1.0 a week or so ago.
Firefly – in my case the latest nightly from about 6 weeks ago running on a NSLU2 NAS device – is definitely still working as a shared music server to iTunes with my installation of iTunes 7.1.1 (as it was with 7.1.0 also).
Front Row on the Mac is also working successfully as a client to Firefly still with iTunes 7.1.1 installed (started working for me with 7.1.0 so I’m glad it wasn’t a false dawn and has indeed continued with the next point release of iTunes).
It doesn’t seem to be an overall problem then affecting all users. To the OP, can your Mac running iTunes 7.1.x successfully display and play music from a “real” iTunes running on another PC or Mac in your network? Have any router or networking changes at all (firmware update to router, change in subnetting or IP addressing within your local LAN, routing through a filtering/caching/routing Linux box which might have had some software or config change, etc) been made since Firefly->iTunes was working with iTunes on that Mac?
I’m not sure I can add any useful advice other than the above, but hopefully the fact that I have an Intel Mac running iTunes 7.1.1 and Firefly svn-1489 running on a Linux-based NAS and that it _is_ working without any particular configuration should at least give you hope that it is “just” a configuration issue rather than overall brokenness.