Session has expired

I just got a message when trying to post in the forums, that my session had expired and I had to log in again. The odd thing is that I was still logged in. It hadn't taken me THAT long to type my message, it was only a couple of sentences, and I type 80 wpm.

I had to close out that page completely, and re-open that forum thread, in order to re-type the reply and have it accept it. I don't know if you have any control over the forum code (probably not), but I thought I would report it anyway.

I have a static IP address, which only changes if our router is rebooted. Since I am the only one in this house who reboots the router, I know that isn't what caused it this time.

This has actually never happened to me before. Which is making me wonder if the new version of Norton that I installed two days ago isn't doing weird things to my web games somehow. If that's the case, I just hope it settles itself down soon. Otherwise I'm afraid I'll go crazy.