public function SlideShow( ){
     //If you are working locally on your computer, you will load manually load the xml file.  Otherwise you will be receiving the xml file from SWFObject2
     xmlURL = ( getDevelopmentMode() === "Production" ) ? getFlashVars().xml : "./xml/data.xml";

     //Capture where the SWF is living on the live site
     var currentLocationOfSWF:String = getContextPath();
}

private function getFlashVars():Object
{
     return Object( LoaderInfo( this.loaderInfo ).parameters );
}

private function getDevelopmentMode():String
{
	var dev:Boolean = new RegExp("file://").test( this.loaderInfo.loaderURL);

	if( dev ) return "Development";
	else return "Production";
}

private function getContextPath():String
{
	var uri:String = getLoaderURL();
	return uri.substring(0, uri.lastIndexOf("/")) + "/";
}

private function getLoaderURL():String
{
	return this.loaderInfo.loaderURL;
}

These are my favorite helper functions.   getFlashVars() is used to quickly pull out variables from SWFObject2, getDevelopmentMode() is used to determine whether you are working locally on your machine or if the SWF is hosted on a server,  getContextPath() is used to determine what directory the SWF is located

AS3: My favorite helper functions

ActionScript 3