I’m getting almost exactly the same thing, but with a very different setup.
Wired PC :- XP pro running firefly 1.0 svn-1359
Wireless laptop :- XP pro running iTunes 7.4.3.1
My Roku branded M1001 using wireless are both able to connect to the firefly share and play VBR mp3s (over 4 hours today without a hiccup).
However iTunes on my laptop initially sees the share. When I connect to it it starts loading the database then without any error messages drops back to the local music library and the share disappears. It looks like it’s dropping out at the exact moment it’s finished loading the library and should then be sorting the list of available files.
The only way to see the share again is to close and restart iTunes.
Before I installed firefly I had iTunes 7.4.3.1 running on the same wired PC working fine serving to the M1001s and to my laptop.
There are no errors in the firefly log. My library is 9286 tracks.
What can I try?