Several times over the past few days, I've entered a post, submitted it, and come up with an 'invalid session' error (all on the Physics/Astronomy forum, IIRC). And when I hit the back button, the post I entered has all gone and I have to retype it again


This is really frustrating, to say the least. I've tried logging out and back in again and the problem hasn't gone away. I've not changed my web browser either (IE 6.0).
Is anyone else having this problem or is it just me? Is there a solution?