Dynamic menus with nav_menu in Product Theme

I am working on a replacement for the built in navigation system in the Product theme and need some help to get it operational.

The goal is to produce TopNavigation and SubNavigation menu bars (in the same locations as the current navigation and buddypress menus) where hovering over or clicking on any item in TopNavigation will produce a corresponding menu in the SubNavigation bar. I am working off the approach described here: http://woork.blogspot.com/2008/05/pastel-color-menu-with-dynamic-submenu.html

To do this, I’ve

1. Created a child theme

2. Altered the header.php file in the root by

including the following JQuery script at line 62:

<!-- Script for dynamic submenus -->

<script type="text/javascript">

function showsubmenu(id){

submenu=document.getElementById('s'+id);

for(i=1;i<=6;i++){

if(i==id){

submenu.style.display="block";

} else{

document.getElementById('s'+i).style.display="none";

}

}

}

</script>

<!-- End dynamic submenus -->

and by commenting out this code at line 175:

<?php if( $bp_existed == 'true' ) { //check if bp existed ?>

<?php locate_template( array( '/library/components/buddypress/buddypress-navigation.php' ), true ); ?>

<?php } else { // if not bp detected..let go normal ?>

<?php locate_template( array( '/library/components/navigation.php' ), true ); ?>

<?php } ?>

and replaced it with:

<?php locate_template( array('/library/components/alt-nav.php'), true ); ?>

3. Created an alt-nav.php file (attached) which contains the menu layouts as described on the site above.

4. Created a functions.php file in the _inc subfolder which registers submenus corresponding to each of the topnavigation items using register_nav_menus().

I haven't yet worked on any styling because the menus fail to load at all right now and I've no idea what I'm missing. You can check my work at http://www.alongside.org/new/

Any suggestions?