Popup Plugin not working

Hi,

The Popup Plugin doesn't work on my website http://www.myperfectprom.com. The website is built using iThemes Builder. I would like to use an image an advertisement for the Popover and have entered the link to where the image is stored on my website but it doesn't work. I have also tried entering just plain text in the Popover content window but it still doesn't work. Can you help please?

Brian