Creo que ya te entiendo:
Deberías poner el script dentro de una función:
Código:
<script type="text/javascript">
function repro(){
var gn = new SWFObject("http://source.netandino.com/player/player.swf","gnmpl","920","32","9");
gn.addParam("allowscriptaccess","always");
gn.addParam("allowfullscreen","true");
gn.addParam("wmode","opaque");
gn.addVariable("file","URL DE MI RADIO?type=.mp3");
gn.addVariable("duration","00");
gn.addVariable("provider","video");
gn.addVariable("bufferlength", "3");
gn.addVariable("autostart", "true");
gn.addVariable("skin", "http://source.netandino.com/theme/stylish_slim.swf");
gn.addVariable("quality","true");
gn.write("gnplayer");
}
</script>
<button onclick="repro()">Reproducir</button>
Sin olvidarte de poner el div anterior