The AutoResponse Plus backup file is a MySQL generated sql-dump. Each backup created uses a unique name, so no previous "dump" will automatically overwrite the others.

The backups (dumps) are stored in your /arp3/backup/ directory (where your ARP scripts run) on your server.

This is typically:

/home/username/cgi-bin/arp3/backup/

Note: the path is different for Ensim, Plesk, and other hosting administration control panels.

You would ftp into your account to manage them.