Unpredictable display of objects

Need help with a strange problem. New at actionscript so code may be inefficient. Application loads an xml file and uses a node to load an image (swf) and create a class for the loaded object. Another as file loads the xml file again and uses nodes to create a tiled display object out of the loaded images in the first object class. The problem arises when I try to build the tiled display. If I keep the number of objects down to 3 or 4 the tile display seems to work. If I try and build a tile display 15 by 10 it breaks down. I never know which objects will show up in the tile display.