Raspbmc file access

I am running 1.4.1.2 Servio on a Mac. Using raspxbmc I can browse music file on the server but when I attempt to play a file an aac file get an error on the pi. I play the file if a browse through a SMB share so it is not a case that raspbmc cannot decode the file. Looking at the logs it appears that there is an access problem or possibly a misreported codec. This is so close - is there any insight? I can play other file types through upnp - mp3 being one.

Any heep greatly appreciated,
Al