seems to have done the trick!
Thanks Ray, again. I've removed that code from cssmw/menu.asp and it's solved the problem. I've done some changes on the menu, since, and it doesn't appear to have put that code back so I'm guessing that's problem solved.
In answer to the original question though, there shouldn't be any problem running the menu on a .shtml page, should there?
Thanks again for the assistance.