Flash/XML loading

I read your tutorials about loading XML into Flash and I pretty much copied it word for word and for some reason, my XML document is not loading correctly. Did I do something wrong/type something incorrectly? Neither trace message appears.

var profile_xml = newXML();
        profile_xml.ignoreWhite=true;
        xmlpercent = (profile_xml.getBytesLoaded())/(profile_xml.getBytesTotal())*100
        profile_xml.onLoad = function(success){
    if (success){ 
    trace("Yup, it loads")
    } else { 
    trace("Error loading XML file")
        }
        }
        profile_xml.load("profiles/mshtien.xml");