Hi all,
I was experiencing this problem too and have managed to implement a temporary workaround to enable me to play FLAC (which is most of my library).
For anyone that's intersted in getting FLAC files to play until the next release here's what I did :
1. Looking at Carlos's log, it seems that XBMC is looking to load a library from Library not loaded: /opt/local/lib/libogg.0.dylib (probably an old linux reference since /opt does not exist by default on OSX I think)
2. Make the directory /opt/local/lib from the terminal if it does not exist on your system. (mkdir /opt/local/lib)
3. You'll find that the the library libogg.0.dylib can be found inside XMBX.app/Contents/Frameworks. Copy this file from here to the directory you created in step 2 using the terminal. (cp /Applications/XBMC.app/Contents/Frameworks/libogg.0.dylib /opt/local/lib)
4. Try playing a FLAC file and enjoy yummy FLAC loslessness.
Hope this is helpful for someone. Disclaimer : it worked for me, YMMV.
Spiderlane