discount rate doesn't work

Hi Tuan,
I just noticed the discount rate has stopped working on the site which makes the site worthless unless I can fix it.
if you get a moment can you logon to the site to see if it is something small. I have a trouble ticket open on it too.
Thanks
John

Checked the site with the client on Skype and It works . It is just something wrong with the testing of clients !

Tuan