Wheel of Fortune

Now it's saying "A term is undefined and has no properties."

I think it has something to do with the XML document. What should I do now?

var xmlRequest:URLRequest = new URLRequest("puzzle.xml");
var myLoader:URLLoader = new URLLoader(xmlRequest);
var puzzle:XML;
myLoader.addEventListener("complete", xmlLoaded);

function xmlLoaded(e:Event):void{
puzzle = XML(myLoader.data);

var myAnswers:Sprite = new Sprite;
myAnswers.name = "letters";
answers_mc.addChild(myAnswers);

var letters:XMLList = puzzle.children();
var numAnswers:int = letters.length();
var i:int = 0;

for(i=0; i<numAnswers; i++){
var myAns:Answer = new Answer();
myAns.answer_txt.text += letters[i].toString();
}
}