There's two elements to having a popup-menu in vB3 ...
(the first examples are from my Flash Player addon - see working site example @ www.mobileforces.org)

1) the entry on the (navbar) template where you want it to popup
<td id="flashplayer" class="vbmenu_control"><a href="#flashplayer">$vbphrase[flash_addon_title]</a> <script type="text/javascript"> vbmenu_register("flashplayer"); </script></td>

2) the actual menu
<div class="vbmenu_popup" id="flashplayer_menu" style="display:none">
[ all your <table, tr and td stuff goes here ...]
</div>

In the (navbar) template where you specify the Link name, you must specify a unique label for the <td id="a_unique_label" ... for example if your label was "somelabel", the item on the navbar would be as follows:

<td id="somelabel" class="vbmenu_control"><a href="#somelabel">Some Label</a> <script type="text/javascript"> vbmenu_register("somelabel"); </script></td>

and the menu must then be as follows:

<div class="vbmenu_popup" id="somelabel_menu" style="display:none">
[ all your <table, tr and td stuff goes here ...]
</div>

If you want there to be two menus with the identical contents, in different places on the same page, then you will need to make two menus with unique "somelabel" entries in both positions ...

Please let me know if I can make this clearer :D