getURL = undefined (XML)

programming flash
1

hello, i am have a slideshow fed by an XML file. I am trying to add external links to each of the main pictures. But I get site.com/undefined

Here is the AS:

MCXML = new XML();
MCXML.load("albums/photos1.xml");
MCXML.ignoreWhite = true;
MCXML.onLoad = function(succes) {
    function Pic_Desc(n, u, g) {
        this.name = n;
        this.url = u;
        this.go = g;
        this.small = undefined;
    }
    if (succes) {
        //extraction des images du fichier XML
        var i = 0;
        while (this.firstChild.childNodes* != undefined) {
            _root.PIC* = new Pic_Desc(this.firstChild.childNodes*.attributes.nom, this.firstChild.childNodes*.attributes.url, this.firstChild.childNodes*.attributes.go);
            if (this.firstChild.childNodes*.attributes.mignature != undefined) {
                _root.PIC*.small = this.firstChild.childNodes*.attributes.mignature;
            }
            i++;
        }
        _root.MAX = i;

        button_btn.onRelease = function() {
        getURL(this.go, "_blank");
        };

Here is an extract of the XML:

 <photo nom="Love in New York" url="http://farm1.static.flickr.com/102/316119849_0001a45a58_o.jpg" mignature="http://farm1.static.flickr.com/102/316119849_0001a45a58_s.jpg" go="http://www.flickr.com/photos/angel_girl_x/928657526/in/set-72157604069725065/"/>

Can you please help me understand what’s is wrong?

Thank you,

Marine