Placement problems

hello everybody,

i’ve got a movieclip wich loads .jpgs dynamicly into another movieclip (a holder)… but i’ve got some problems with setting the x and y values of this holder…

goto http://www.base-ment.com and choose Foto’s as you can see the thumbnails aren’t aligned properly…

here are the actions for a thumbnail:
frame1:


holder._alpha = 0;

frame 2:


var dir = _root.gedrukt;
laad = "Flash/source/"+dir+"/thumbs/"+this.http;
groot = "Flash/source/"+dir+"/"+this.http;
holder.loadMovie(laad);

frame 5:


holder._alpha = 100;
if(this.origb>this.origh){
 holder._y = (80-holder._height)/2;
}
if(this.origb<this.origh){
 holder._x = (80-holder._width)/2;
}
stop();

who knows whats wrong and can help me out?