error when using Wholesale Order Form Plugins

Hi Support,

There is a error when using Wholesale Order Form, Our testing site : http://healthcare.hkccfl.station199.com/wholesale-ordering/

Point 1 : when click “add to cart” first time, the blank pop-up appear.
Point 2 : when click “add to cart” second time, the system is keep on loading.

image captured : http://healthcare.hkccfl.station199.com/001.png

Please Advise.