If you have the option to display all errors on page (Tools > Internet Options > Advanced > Browsing > Display a notification about every script error), you'll get several errors when you click on any of the pop-ups.
Where can you find these buggy pop-ups? There is a CopyrightInfo link down at the very bottom right of the footer, and also, if you click the Latest Gallery Piece picture, you'll get errors too.
Right-click > View Source to see my code. Any help would be greatly appreciated.