Just had this problem myself.
The problem is in the XP SP2 firewall. My stupid ass turned it on, when I had another firwall already running. When I went to turn that micro$oft P.O.S. off, it would not TURN off.
Sure it would say it was turned off on one screen, but not the other. Nothing would turn it off. Firefox, and every other program worked fine, except I.E.. So what I did to correct it was uninstall one of the firewalls, and go into internet options on I.E. resetting all to default, and then reinstall one of my secondary firewalls.
Problem solved.
The problem's in XP SP2 firewall that creates the problem you are having. The is prolly another work around, but that one (above) worked for me.
