Apple has updated Backup to v3.1.2. You can download the update from its Web site.
Backup is the backup and archival tool provided to Mac users as part of Apple’s .Mac subscription service. Backup lets you archive data to DVD and CD or online or to other hard disks. It features presets that enable you to back up iLife content, personal settings and your home folder, assign schedules to backups and more.
Backup 3.1.2, highly recommended for all users, includes reliability improvements, according to Apple. It also improves compatibility with Mac OS X v10.5 “Leopard.”