Undefined variable $database_file

Hello,
Creating a new database Backup I’ll get the warning:
PHP Warning: Undefined variable $database_file in /data/web/xxxxx/wp-content/plugins/wp-database-backup/includes/admin/class-wpdb-admin.php on line 1634
and
PHP Warning: Undefined variable $filename in /data/web/xxxxxx/hubi/wp-content/plugins/wp-database-backup/includes/admin/Destination/FTP/preflight.php on line 29

Creating a Full Backup
I’ll get the message.
Delete old Backup: (but there is no old Backup)
and the same as above 1st one.

But both Data Backup are well done.

Any Solution??