Uncaught ReferenceError: wp is not defined

I am trying to get this plugin to work.
If I am logged in as an Administrator, all works as expected.
If I am not logged in the submenus do not expand on hover (as it should) and I get 2 errors in the Console:

(index):1485 Uncaught ReferenceError: wp is not defined
    at (index):1485:1328
(anonymous) @ (index):1485
(index):1034 Uncaught TypeError: jQuery(...).wpdevart_vertical_menu is not a function
    at HTMLDocument.<anonymous> ((index):1034:28)

The page I need help with: [log in to see the link]