Why I cant see the text? (XML Problem)

programming flash
1

I have a flash with just 2 frames with code.

// First Frame Code
var userInfo = new XML();
userinfo.ignoreWhite = true;
userInfo.load('userInfo.xml');
menu_xml.onLoad = function (success)
{
	if (success)
	{
if(success == true) gotoAndPlay(2);
	}
	else
	{
		error_txt.text = "Error loading xml data...";
	} // end if
};

 //Second Frame Code 
userInfo.onLoad = function() {
XMLOut(this);
}	 
function XMLOUt(xml_file) {
for(a=0;a<xml_file.firstChild.childNodes.length;a++) {
for(z=0;z<xml_file.firstChild.firstChild.childNodes.length;z++) {
trace(xml_file.firstChild.childNodes[a].childNodes[z].firstChild.nodeValue);
}
}
}

I have the XML file and the SWF in the same directory, but I get always a blank flash preview. What I’m suposed to change in order to make the flash dislay the data I’m asking for?

Thanks for the info!