Urgent help

for those who are got talent in flash AS
please, how can I make multiple rows of the thumbnails given here and control the number of columns.
AS:

myPhoto = new XML();
myPhoto.ignoreWhite = true;
myPhoto.onLoad = function(success) {
//portfolioTag = this.firstChild;
numimages = this.firstChild.childNodes.length;
spacing = 100;
yspace = 20;
var columns=2;
for (i=0; i<numimages; i++) {
images++;
this.picHolder = this.firstChild.childNodes*;
this.thumbHolder = thumbnails.createEmptyMovieClip(“thumbnail”+i, i);
if (images>=howManyLong) {
yspacing++;
yspacing = Math.acos(30)yspace/10;
images = 0;
}
this.thumbHolder._x = i
spacing;
this.thumbHolder._y = i*yspacing;
thumbHolder._y = Math.floor(i/columns)*thumb_spacing;
this.thumbLoader = this.thumbHolder.createEmptyMovieClip(“thumbnail_image”, 0);
this.thumbLoader.loadMovie(this.picHolder.attributes.thmb);
this.thumbHolder.title = this.picHolder.attributes.title;
this.thumbHolder.main = this.picHolder.attributes.main;
this.thumbHolder.onRelease = function() {
loader.loadMovie(this.main);
title_txt.text = this.title;
};
}
};
myPhoto.load(“xmlphoto.xml”);
any single data is much appreciated