If you are experiencing crashes when you update your mpd library on Ubuntu 12.10, the fault is with libmad0.
This can be fixed by installing libmad0 from Debian Wheeze. As root:
wget http://ftp.us.debian.org/debian/pool/main/libm/libmad/libmad0_0.15.1b-7_armhf.deb dpkg -i ./libmad0_0.15.1b-7_armhf.deb
I can confirm that this has fixed my update crashes. When I get to the box itself I'll confirm whether audio playback still works!