Target a button inside a mc in order to trigger a sw

1

Hello everyone,
Trying to target a button inside a mc in order to trigger a swf. The swf has the same name as the listener in order to repeat the function with multiple swfs. my problem is, i’m getting an error of an Access of undefined property with my mc

I geting an error:"

1120: Access of undefined property nav_btns.

var Xpos:Number = 461;
var Ypos:Number = 294;
var swf:MovieClip;
var loader:Loader = new Loader();

var defaultSWF:URLRequest = new URLRequest(“swfs/nav_btns.contact_btn.swf”);

loader.load(defaultSWF);
loader.x = Xpos;
loader.y = Ypos;
addChild(loader);

function btnClick(event:MouseEvent):void {

removeChild(loader);
var newSWFRequest:URLRequest = new URLRequest("swfs/" + event.target.name + ".swf");
loader.load(newSWFRequest);
loader.x = Xpos;
loader.y = Ypos;
addChild(loader);

}
// Btn listeners
nav_btns.contact_btn.addEventListener(MouseEvent.CLICK, btnClick);
nav_btns.service_btn.addEventListener(MouseEvent.CLICK, btnClick);