Transition effect fails in xml load

programming flash
1 
var thumb_spacing = 40;
// load variables object to handle loading of text
var description_lv = new LoadVars();
description_lv.onData = function(raw_text){
description_txt.text = raw_text;
}
function GeneratePortfolio(portfolio_xml){
var portfolioPictures = portfolio_xml.firstChild.childNodes;
for (var i = 0; i < portfolioPictures.length; i++){
var currentPicture = portfolioPictures*;

var currentThumb_mc = menu_mc.createEmptyMovieClip("thumbnail_mc"+i,i);
currentThumb_mc._x = i * thumb_spacing;

currentThumb_mc.createEmptyMovieClip("thumb_contai ner",0);
currentThumb_mc.thumb_container.loadMovie(currentP icture.attributes.thumb);

currentThumb_mc.title = currentPicture.attributes.title;
currentThumb_mc.image = currentPicture.attributes.image;
currentThumb_mc.description = currentPicture.attributes.description;


currentThumb_mc.onRollOver = currentThumb_mc.onDragOver = function(){
info_txt.text = this.title;
}
currentThumb_mc.onRollOut = currentThumb_mc.onDragOut = function(){
info_txt.text = "";
}
currentThumb_mc.onRelease = function(){
image_mc.loadMovie(this.image);
description_lv.load(this.description);
}
}
}
function loadTheImage (e):void {
TransitionManager.start(image_mc, {type:Wipe, direction:Transition.IN, duration:3, easing:None.easeNone, startPoint:1});
}
loader.contentLoaderInfo.addEventListener(Event.CO MPLETE,loadTheImage);
// xml object for xml content (defines sources for selections)
var portfolio_xml = new XML();
portfolio_xml.ignoreWhite = true;
portfolio_xml.onLoad = function(success){
if (success) GeneratePortfolio(this);
else trace("Error loading XML file"); // no success? trace error (wont be seen on web)
}
// load
portfolio_xml.load("portfolio.xml");