Thanks for all your help!

I uninstalled and re-installed in C:\bb. All working fine.

As soon as I add my own style files in the folder C:\bb\Styles and do a rebuild the "Division by Zero" Error comes back. There is a message saying "No Blanks in Filenames allowed". So it seems my styles with " " in the filename cause the trouble, strange.

Maybe it is not "allowed" to add own styles?

Greetings
Gery