After having restored my site with XCloner I couldn't create any more categories in the Fireboard forum component. Each time I created a new category all categories disappeared when I wanted to save the creation (on backend and frontend). I didn't relate the problem to XCloner as I was not used to firebaord yet and I started a lot of research. Because this didn't bring any results I installed Joomla 1.5 (legacy mode) and Fireboard 1.04 from the very beginning (not using XCloner) and - everything worked!!! Than I made another backup with XCloner and restored the site in a subdomain to see if the backup was ok. Now there is the problem with fireboard again.
Martin