NIS conflicts with javascript on website

Hi,

 

I'm a webdeveloper, and I have some problems with a customer who tries to access this site http://glasshop.dk with Google Chrome and Norton Internet Security plugin installed. The customer is using Windows 8.

When tryieg to access the site, the site console reports of several javascript errors when NIS is active. However when disabling NIS then the problem goes away.

Due to the javascript problems the website design and content is pushed down so the customer only sees a white screen.

 

Any ideas on why NIS conflicts?