There was a complex unix issue on my server here and the site was down for a couple of days. I have now resolved the problem. I had to restore from a backup, so several recent messages will have disappeared from the web interface, but people will have them in their inbox (replying to the particular messages that are lost will result in an error, sorry).,
All is now back to normal, and I look forward to resuming our excellent discussions.
All the best to all from Australia!