I've tried a lot now to install the latest version of the Flash Player but nothing helped.
However, neither the update, nor an uninstall and then reinstall, or an installation in the save worked mode (offline version).
My gatekeeper is configured correctly and I also deleted all Flash Player files from various folders on my computer.
I already tried the "MacUpdate" link and it didn't work as well.
Any other solutions?
My flash player is not working for more than one month now...