jquery sortable ul in a ul not working - jquery-ui

Question

Kind of confused. I have a chunk of code for sorting nested li's that works. I copied the code into another page, and just changed a few class names to match the new pages elements. For the life of me, I cannot figure out why the same code is not working on the new page. Here is the code:
var is_sortable = true;
$(function () {
$('.packaging_move').bind("mousedown", packaging_add_sort);
function packaging_add_sort() {
//CHECK TO SEE IF THERE IS AN ACTIVE SORTABLE
if (is_sortable) {
//GET THE PARENT AND CURRENT ELEMENTS TO THE CLICKED ITEM
var parent = $(this).parent('div').parent('div').parent('li').parent('ul');
var current = $(this).parent('div').parent('div').parent('li');
//MAKE TRANSPARENT
current.animate({
opacity: 0.60
}, 100);
//PREVENT ANOTHER SORTABLE
is_sortable = false;
//CREATE SORTABLE
parent.sortable({
axis: 'y',
update: function () {
var parent_id = parent.attr("id");
var list = parent.sortable('serialize');
$.post("index.php?plugin=packaging&page=index", {
action: "packaging_rank",
parent: parent_id,
items: list
});
parent.sortable('destroy');
is_sortable = true;
},
stop: function () {
current.animate({
opacity: 1.0
}, 100);
parent.sortable('destroy');
is_sortable = true;
},
}).disableSelection();
//IF THERE IS AN EXISTING SORTABLE SHOW ERROR
} else {
zlcms_alert("Sorting Error", "You currently have an instance of sorting initiated. You may only sort one item at a time. Please complete the previous sort and try again.")
}
}
}