XML Error ( TypeError: Error #1010 )

[uAlpay]

TypeError: Error #1010: A term undefined and does not feature.
at index_fla::MainTimeline/onLoaded()
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at flash.net::URLLoader/onComplete()



var xmlPort:XML = new XML();
var xmlURL:String = "/portfolio.xml";
var xmlReq:URLRequest = new URLRequest(xmlURL);
var xmlLoader:URLLoader = new URLLoader(xmlReq);

xmlLoader.addEventListener(Event.COMPLETE,onLoaded );
xmlLoader.addEventListener(ProgressEvent.PROGRESS, onProgres);
var loadTf:TextField = new TextField();

function onLoaded(event:Event):void {

xmlPort = XML(event.target.data);
removeChild(loadTf);
for (var i:int = 0; i < 25 ; i++) {

var box_i:Box = new Box(0x444444,0x222222,xmlPort.item[i].name," / " + xmlPort.item[i].year);
box_i.x = 250;
box_i.y = i * 40;
sprite.addChild(box_i);
}

}

function onProgres(event:ProgressEvent):void {

loadTf.text = "Loading Data";
loadTf.textColor = 0x000000;
loadTf.autoSize = TextFieldAutoSize.LEFT;
addChild(loadTf);
loadTf.x = stage.stageWidth / 2;
loadTf.y = stage.stageHeight / 2;
}



It gives this error but it works fine after i click continue . What is that ?



var box_i:Box = new Box(0x444444,0x222222,xmlPort.item[i].name," / " + xmlPort.item[i].year);

the problem is up that line . And here's my XML file


<?xml version="1.0" encoding="utf-8"?>
<portfolio>

<item>

<name>
Snake catching bird
</name>

<year>
2008
</year>

<content>
/images/1.jpg
</content>

</item>
<item>

<name>
Dragon
</name>

<year>
2005
</year>

<content>
/images/2.jpg
</content>

</item>
<item>

<name>
3D Building
</name>

<year>
2006
</year>

<content>
/images/3.jpg
</content>

</item>
<item>

<name>
2D Space Game
</name>

<year>
2009
</year>

<content>
/images/4.gif
</content>
</item>
<item>

<name>
Snake Eye
</name>

<year>
2004
</year>

<content>
/images/5.jpg
</content>
</item>
</portfolio>