Please note that official support for this menu version has now ceased. There are still plenty of users, though, and the forum is still running. Some of our long-time users may be able to help you out.
I haven't been able to make my menu display properly on any version of Explorer on any Mac computer. The URL: http://www.gcc.mass.edu/library
Should I just upgrade to 5.0? Will that help? We're using some very clunky JS navigation on our main page, http://www.gcc.mass.edu, and would love to switch to this menu if I can make it work better.