As you know, UPnP support on the PhotoBridge can be a bit hit-or-miss. I've come across a new UPnP server that seems to work great. Its audio only, but it supports a great range of audio codecs including MP3, WMA, Apple Lossless and FLAC (and WavPack though the documentation doesn't mention it).
http://www.dbpoweramp.com/asset-upnp-dlna.htm