yeah, you have to ensure libvorbis is installed. I have version 1.3.4 (on Gentoo Linux). You also need libogg, but libvorbis depends on libogg, so if you install one, your package manager will pull in the other as well. You also have to ensure that SDL is compiled with ogg/vorbis support (not sure how ZorinOS works, but it's the "vorbis" USE flag in Gentoo).