There are a variety of reasons that you might not be able to run multiple audi tracks. From memory in KDE you need to enable arts, which does that, but i could be wrong.
The main reason everyone is talking about ALSA is that it is the default sound driver in the 2.6 series kernel. I was like you and thought i'd check it out on 2.4, before i took the 2.6 plunge, and with similar results, nothing worked so grand.
That said, 2.6 works great, and all is well. So you might want to try that out. Of course that is a different kettle of fish ... but strangely enough a kernel compile is far more straight forward than a alsa install. (To my way of thinking anyway).