Can't display any data in array while parsing XML file

I try to parse a xml file into an array. For some reason I don’t understand WHY I can’t see any datas in my array (tab_test) when I traced it from outside of the function.
Btw, my tab_test is a global variable.

It doesn’t make sense. It’s that something to do with flash cs3 garbage collector?? It deletes it??
(I tried to understand WHY that could happen…)

It gives me an error message saying there’s no contains in the array null object something…
Obsviously, my tab_test.lenght = 0

public var tab_test:Array = new Array();

// call it in constructor
_initXMLFile();

for(var i:uint=0;i<this.tab_test.length;i++) {
trace('TabTest: '+this.tab_test*.file);
}

private function _initXMLFile():void {
this.loader = new LoadXML(“xml/images.xml”, _onDisplayTest);
}

public function _onDisplayTest(evt:Event):void {
this.xmlData = new XML(evt.target.data);

for(var i:uint=0; i<this.xmlData.images.length(); i++) {
this.tab_test.push({file:this.xmlData.images*.item.toString(), view:this.xmlData.images*.object.toString()}) ;
trace('TabTest: '+this.tab_test*.file); // it’s working fine here, I can see datas
trace('TabView: '+ this.tab_test*.view);
}
}

XML file:
<bitmap>
<images>
<item>images/img_01.jpg</item>
<object>face1</object>
</images>
<images>
<item>images/img_02.jpg</item>
<object>face2</object>
</images>
</bitmap>