Unfortunately, the code was being flaky on IE; not launching reliably, so last night I started digging into it. The script itself was inaccessible, and after a 1/2 hour or so of tearing apart the HTML, looking for some issue, I punted. Went and hunted up a different script.
Then spent an hour or so merging the new script with the old menu, and reformatting the menu (colors, fonts, etc.)
Finally, took a look at it in Firefox (I usually use IE on the laptop at home, Firefox at the office) and the page barfed. So another hour of troubleshooting. Turned out I had left rogue "/li" commands at the end of each menu item (the old script made submenu choices a separate list item, the new one did not).
So, problem resolved, pages up and happy, all is right with the world. And I killed 3 hours on a Tuesday night wrestling with this stuff, did not get to bed until close to midnight. Yech.