The forum was moved to a new server during my overnight.
I posted before it was due to happen, but obviously the copy was made before then, so it's not here now.
Something in the file system changed, so we were getting error messages thrown out.
I've fixed what I can find wrong, but if anything still isn't working, let me know. If need be, by the help email top right of the forum header.
I had to remove the Say Thanks option, as something in it was incompatible with whatever changed.
Just what I needed, to start the day with my stress levels in orbit.
But we seem to be back and working now.
The host company didn't think the change would affect anyone, so didn't bother warning people. But it appears all the older php sites, and this version of SMF is getting old, were affected badly.
Anyway, let me know if you still find a problem, or are having a problem.