ZoneAlarm Pro and Firefox problem

[cold_cash]

Howdy folks. I'm having a bit of a computer problem and I'm wondering if you can help me out.

Currently I use Firefox as my web-browser and ZoneAlarm Pro as my firewall. If I leave my computer for a period of time, say an hour or so, when I come back and click on a link I often get the "this page cannot be found" message.

If I shutdown ZoneAlarm and re-click, everything works like a champ. Also, if I try to open the link or webpage in IE I do not get the error message; it's just in Firefox.

I looked through the ZoneAlarm settings but didn't see anything that stuck out. Any ideas?