Hola!
Wow... I've gotten so into klystrack lately that it never even occurred to me that it's kind of an obscure format! In my head, it was as good as mp3s

Alright, you *will* need klystrack to play it (although I *am* working on a stand alone player as my first bmax project, real life is keeping me very busy atm).
"But it won't load the songs and also I hate your face and your cats aren't very smart!"
Well, first of all. My cats are adorable. My face, that's subjective opinion. And klystrack? Well, here's the essplanassion:
1.5.4 is the latest stable release
1.6.0 is being worked on at the moment and is currently at revision 1170. Some fairly major changes in the sound engine (changing how noise sounds, and adding LSFR oscillators) are making the two incompatible. In the interest of keeping my songs compatible with the latest version (some of my songs are included in the release package as example songs) I always use the latest nightly build. But yeah, format is not backwards compatible so you'll need the latest version, generally at the top of this page:
http://code.google.com/p/klystrack/downloads/list