ActionScript only works once?

programming flash
1

Hi all!

Im trying to get a dropdown meny to work with my flipbook. The thing is that it works just fine if it runs once, but after the script has been used it won´t work again.

My code:

 
var lo = new Object();
lo.change = function (evt_obj:Object) {
 var dest_page_number =  evt_obj.target.selectedItem.data;
 myBook.flipGotoPage(dest_page_number);
}
combo_mc.addEventListener("change", lo);
function onInit(){
 number_txt.text = pageNumber;
 lo.book = myBbook;
}