[ReVo_]

Audio_PlayStreamed returns an handle, maybe you should use the handle returned by Audio_PlayStreamed.

Код:

stock Function(playerid)
{
        Audio_Set3DPosition(playerid, Audio_PlayStreamed(playerid, "http://yp.shoutcast.com/sbin/tunein-station.pls?id=656213", false, false, true)
, playerPos[0], playerPos[1], playerPos[2], 50.0);
    return 1;
}

try this