It should work just fine if you declare the correct URL to DynarchMenu before loading the main script, like this:

<script type="text/javascript">
  _dynarch_menu_url = "/products/hmenu/";
</script>

<script type="text/javascript" src="/products/hmenu/hmenu.js"></script>
<link rel="stylesheet" src="/products/hmenu/skin-aqua.css" />

The above declares the URL as “/products/hmenu/