It is the code of the original footer.php that I used in the end.
So You can just download the WordPress package and copy the file or the content from there.
Good luck
Maik
I edited the footer.php. There I deleted too much, so that I had to replace the footer with the original source. After that, everything worked fine again.
Was my fault, edited the wrong file, sorry for bothering 🙂
It works now, thank You very much lucymtc 🙂