no drop down menus

hi--

I've developed a site using Nice Menus and it works fine on my server. Moving all the code (copying and pasting) to a new server with exactly the same versions of everything, the drop down menus do not appear.

On the working server, I've never had to check "expand" to make them work. No matter, even checking that where I can doesn't make the site work.

Is there anything else I can check for?

Thank you!