I use Zone Alarm Pro for my firewall and have a strange problem. I load the "View posts since last visit" page and can read the forum for a "while" with no problems, then I start getting "page not found" errors. If I hit the back button, I can get the page I'm looking for a few more times, but then even that stops working.
If I close ZAP, I can continue with no probs, but I don't like surfing unprotected even here. Otherwise I only get to read maybe 30 or 40 topics.