I noticed that the backup files are good if you download them with winscp.
If you download with the web interface it looks like it is tarred twice.
In the backup fromwww.tgz is the folder fromwww.tar in there is a file fromwww.
If I rename the file fromwww to fromwww.tar I can extract it and get the right files.
In the backup fromscp.tgz is the folder fromscp.tar in there are the right files.
The backup from the webinterface is corrupt if you try to restore it.
The backup downloaded with winscp works.