After some problems I succeeded in getting the extension up and running.
It does everything a forum should do - and more! The layout is great and the software is FREE! I reckon it will be a world beater in a year or two!
But there are still some issues, which I have described in a sort of 'User Guide' - which you can find on the ChronoEngine forum. It's called 'User_Guide_to_Chronoforums.pdf'. I am not allowed to publish a link here, but you can probably find it with a bit of searching.