I revived this old thread, which suggests that there is a problem with the Forum every ten years!!
Early in the morning of the 1st January the Forum went AWOL. When I awoke the next day I discovered a number of emails from members who were wondering where it had gone! So, before setting off for my next tournament that afternoon I had a look at the usual suspects, spammers, hackers, etc. and could find nothing odd, so I got in touch with the server hosts who said that no server software had been updated, Very strange,
When I realised that there was nothing I could do I got in touch with the main YaBB software specialist and she downloaded the Forum onto her testbed, Apparently everything worked fine!
She thought that the server host had change something, but might not even know what that was! I asked them again, very politely, but they thought it was a problem with the Forum. Of course, nothing had been changed here for over two years, so it seemed impossible that it could be that.
Nothing was progressing, and meanwhile I had finished my tournament and come home. We decided to move the Forum to another server (as it turns out, to another continent!)
So, to cut a long story short, we have finished setting things up on a new server, we've changed the domain nameservers, and finally we are up-and-running again!
Thanks to everyone who sent words of support and encouragement!