The option in .conf would be:
[daap]
supports_update = 0
You might try turning off “Look for shared music” in iTunes Sharing so you don’t see the Firefly server (I assume you are running iTunes on the same box as Firefly in this scenario) and see if that makes any difference…
Also, as I mentioned above, the invalid metadata errors in the log are known and bugged. (You won’t see them unless you have an active iTunes client talking to the Firefly server.) Probably safe to ignore for now…