Have you tried installing the
Vertex Upgrade Patch?
If that doesn't help, I would also suggest creating a new menu and seeing if the actual menu is the problem. From what I can tell, it looks like every menu item with subtext is missing the URL that it's supposed to link to, but all the ones without subtext are working fine. The Corporate Response demo has subtext on most of the menu items and they all work fine, so it has to be something related to the way your site is configured.
