NIS 2011 blocks webpage most of the time

I am using NIS 2011 but sometimes I uninstall it because it block some chat page I want to use. I can go to the webpage, I can log in, but after a short moment the pages hangs(blocked/frozen how do you say it). After one minute the webpage has been unlocked and after a while it is again locked and then most of the time I can't use it anymore. The page stays blocked.
It is a page where you can chat, I used gdata, trend micro, kaspersky ..none of this software has a problem with this webpage only norton seems to have it.

It's frustrating because I want to use this page, but almost impossible with NIS 2011. If I would get any remark of the software maybe I could solve the problem, but the programm gives no remark, is just blocking the page most of the time(frozen screen). What can I do about, is there something to do about it?
How can I setup NIS2011 so the software accept this webpage?
I turned off the software for by example a fifteen minutes but the problem is still there.

I hope somebody can help me with this problem.