OK, I've had this issue for a while now and still haven't been able to figure it out. For some reason, any time I click a link which has a redirect for advertising such as
http://a.websponsors.com/ or aclick or whatever, it just gives a page cannot be loaded screen.
I thought it might have been my ISP, but I've tried two so far and they both do it. The issue is on FF, IE and Opera... and I also have Norton AV auto-protect disabled (although back in the day .. or back when I can remember.. I never had this issue with Norton .. plus I haven't updated it in a while).. I can't think of any other programs that are currently running that would block this...