I am new to the field of web design.

1) I drag dropped one of the designs at random from the gallery.
2) I clicked on the navigation menu and simply renamed the "Blog" tab to "Discovery".
3) I saved then exported the website to my test directory.
4) I uploaded this website to my test site using Filezilla.
5) I browsed to it (http://www.greenmenus.biz/IDG).
6) Now, whenever I move the mouse to the navigation menu, the whole menu is highlighted.
7) Clicking on any submenu pops up a small blank screen (I'm not sure how else to describe this).
8) Nothing else happens.

Since I did not alter anything within the code or screens which control the nav menu, is this a bug?