Hi Greg,
ginnyrose already mentioned this in the News Forum in the thread about Real ID in which you posted.
I also am getting this error message over the last 12 hours.
But, the post goes through first time. The screen shows the 'thank you for your submission' then instead of taking you to the thread, tells
Error - this thread does not exist...
The other thing not happening, is that the screen showing all the forum options simultaneously, is not changing to reflect the last post. Or, this is happening only to the News Forum, where three of us have posted since you, but only your name is showing in the forum summary screen.
I think you're very clever to be able to fix these things, and most impressed it all works so well so much of the time. All grace to you.