OK. I managed to remove the activation keys by uninstalling S12 and running regdelete as well as removing entries from the prefetch map and turning off automatic system recovery(!) Only then I could re-enter my serial number and started without any plugins...
But still no luck. Now I got a hang from the programm while writing frames during Make Movie.
To make things more clear: I recently changed my motherboard and therefore had to do a new install of Windows XP followed by S12.
The project was almost finished in the old situation and I did not get any errors or hangs then.
As soon as I had reinstalled S12 the problems began (on a fresh enviroment!)
The only thing I changed after changing my mobo was introducing Dolby and Divx...
I even installed S12 on a second computer and got the same export error.
So at the moment I am pretty stuck how to proceed.
Regards, Peter