Thank you Men, but that isn't the problem. I found out that my server was restarted and the RMS not. So after restart RMS as well, I was able to reinstall the whiteboard. But now it say it isn't installed when trying to use it. But it is installed. In modules folder, in admin folder everything ok there.
I guess I may have to reinstall an another mod with the whiteboard associated? I don't know. Before the upgrade it works. An another possibility is that something in RMS for whiteboard had changed.
Any advice what's the case for an definetly with all green + signs installed whiteboard showing then by click on it as member: Not Installed?