Hello all, thank you for all the testing! Today I make another attempt to import this files who are rejected yesterday. By just doing as Hans has done,.using the Zip- file, out of sudde I could import without trouble. Funny for some reasons but a happy ending.
I can't analysis the error why files are rejected in first and the accept, but it just means: never give up trying.

Again a thank you for the support and troubleshooting.