Hello,
If it's working on one page and not another that means there is a javascript conflict on the pages it's not working on which breaks other javascripts on the page (the menu). I see this error on your homepage:
TypeError: $(...).tooltip is not a function
Typically this happens because of a third party extension that is causing a conflict. You will need to first see if an extension is interfering by disabling all third party extensions and then try loading the page again, this includes plugins.
If that still does not work please be sure you are running the latest version of Joomla; some versions of Joomla had similar errors with javascript tooltip calls. Also, be sure you are running the latest version of Vertex:
http://www.shape5.com/documentation/Vertex-Framework/Joomla-Specific/How-To-Patch-Vertex-In-Joomla-and-Changelog