Hello Krileon,
I want to thank you very very much for this professional support.Everything works fine now.
I deinstalled the componet fgallery a few days ago, but it seems, that the plugin still remained. The deinstallation was managed without any error message.
I just tried to deinstall the plugin, but this does not work. So I will contact the developer of this plugin, to get rid of it.
Once again, thx great work
GTvB