Right, he's managed to get one post in this morning, but now it's doing it to him again with a vengeance. He's tried OTPTT's trick of holding the reply button down for a few seconds and it makes no difference.
We've pinned it down to beginning after the last time the forum was changed in looks, and based on that and google research, he wonders if something like this might be the cause.
http://www.vbseo.com/f2/security-tok...matched-27603/