thanx for the reply!
But it didn;t seem to work...
Now the forum completely disappeared and even reverting yields empty pages now and a time-out on the homepage...
bbPress2.0 and Buddypress1.5 are maybe not all that ready for each other yet in combination with a multi-site setup...
Also when I try to enable this option:
New! Site Wide Forums
Your site will have central forums that are not isolated to any specific group. Choose this if you'd like to have a central forum area for your members.
You may activate both Group and Site Wide forums, but this may create a poor experience for your members.
Central Discussion Area
Forum Plugins Available
Activity Stream Integration
@ Mention Integration
It redirects me to the plugin of bbPress2.0 to install it. But then it finds I already installed it and leaves me there... and enebling the Site Wide fora is impossible...