how to set it?
and
in postality knights it always say failed to iniatilize direct X audio
Right. To set start party position, open up your game, Press F8 (in RMXP), or F7 (in Rm2k/3). Right click where you want the hero to start, and at the bottom you should see a Set Starting Position option.
Note: The starting position cannot be on top of another event, or an impassable tileset. Otherwise the hero WILL be stuck.
Oh and you probably need Direct X Audio to play music, and sounds. You should find it here (http://www.microsoft.com/windows/directx/default.mspx).
Did that help? Anything else?