Onlinefamily.norton.com Stopped working in firefox

Hi

I am using the latest version of Firefox 3 on a XP SP3 PC and have successfully been using the product and website for a few weeks now. This week however when I click on the link in the Email notification I simply get a blank page. I tried using IE and all works fine. I haven't knowingly made any changes and it is the same on a couple of PCs. Any idea what is going on?

 

Many Thanks

Paul