addChild is replacing previously added child

I certainly do not understand what is happening here.

The code below is called after a thumbnail is generated and available. It is supposed to add the thumbnail to a MC along with the file name. The first go around (after a file is uploaded and converted) works, but the second time around the 2nd MC is generated and placed on stage with the correct file name and thumb image, but the first thumbnail image disappears (the file name stays).

I don’t understand why.

function initlistener(e:Event):void{
    myURLFILE = "myURL";//reset URL
    var l:MovieClip = new listBox();//generate listbox
    l.nameof.text = myFile;//populate text field with file name
    l.thumb.addChild(myLoader);//add image to listBox
    var babes:Number = Newcontainer.numChildren;//gets number of children
    l.y = 25 * babes;//positions the listbox vertically
    Newcontainer.addChild(l);//popluates container with listbox
    l.thumb.addEventListener(MouseEvent.MOUSE_DOWN, pickUp, false, 0, true);