I think the diappearance of icons is down to permissions in the CBB administration. Make sure you have given yourself permission to add poll, add topic and reply. (check the drop-down list top left of the pernmissions screen.
Getting back to the original problem I logged - I couldn't get any support from anyone, it seems the CBB support is pretty poor right now judging by the number of people that have posted on this topic and received no reply. If CBB is to really to be the continuation of XOOPS main bulletin board, I hope that the support can get better.
What I ended up doing was installing the module from scratch with no data - this at least seemed to work fine.
Then I created the categories and forums from my old forum manually. I imported the topics and text using SQL and then had to do sum patchwork manually matching up category anf forum numbers. Luckily my forum was not too large at this stage - I don't recommend doing this if you have a large forum as it is a lot of fiddly work. It seems the categories and forums tables didn't like the upgrade.

