[linux-audio-user] Sound servers conflict

I am posting this message a second time as I suspect I did something wrong the first time. Excuse me if both messages arrive. Hi all, I am new to the list and new to Linux audio. I wrote a simple QT program that uses sound, and it requires the NAS sound server. I installed NAS from Mandrake rpm's rebooted the box, and the program works great. The problem is that most of my other software, for example Amarok, stopped producing sound. Prior to installing NAS, I used KDE and there sound server aRts. When I start Amarok I get a message from aRts, that it can't open device for playback. I thus have two questions: 1. Is there a way to resolve such a situation, in a way that allows two programs that use different sound servers to play sounds at the same time? 2. A more basic question: Why do we have to use sound servers in Linux? shouldn't it be the job of the operating system to allow sound multiplexing through a set of standard API's? The situation is especially bad, if there is no comfortable solution to the problem in my first question. Thanks, Hillel.