I love the functionality of the plugin, unfortunately this has occured repeatedly and I was forced to remove it. Here is a typical log:
2011-04-16 03:04.46: Result of table optimize for wp_eshop_orders is: Table is already up to date
2011-04-16 03:04.49: Result of table optimize for wp_eshop_rates is: Table is already up to date
2011-04-17 03:02.06: [ERROR] Backup Aborted working to long!!!
and in another log
2011-04-17 03:02.06: [WARNING] Working Job will closed!!! And a new started!!!