Ubuntu KVM running Win7 iTunes Home Share

I recently built a NAS. It runs Ubuntu 12.04 Server (headless). I just installed Windows 7 via KVM. The network is bridged, and I can access the Plex Media Server on the host, but when I turn on iTunes in the Windows virtual machine, I can't see any of the other iTunes libraries on my network, and the other computers can't see the Windows iTunes library.

I've already enabled sharing on all iTunes libraries, and my wife's MacBook and mine can see each others libraries. All network clients are in the same subnet, including the Windows 7 VM.

Any ideas on why iTunes isn't sharing in or out from Windows 7? (I already disabled the Firewall and enabled all ports that iTunes/Bonjour use.)