I tried a clean install on another linux.
- backuped an empty course in 1.3.1
- restore... same error, so it is not the old zip file as you suppose
- check the settings: (spelling error) thanks
Now the old server backups: works OK, they skip not implemented moduls, nice
Now the old server: ALSO a spelling error, so it works?... YES YES YES
THANKS for the hint
I only make some mistake with the data in the dirs