I have changed my profile now...
Tahnks for your messages!!!
I remind of a repair process of MSOffice in the last days of the last year and I think now that the described error comes after that repairing...! So the Office should be up to date.
I wrote that I haven't IExplorer, my standard browser is Firefox (57.0.4, 64Bit). How can I try the mentioned links?

Regards - Dietrich