Backup cron does not work?

[allenlook]

Unless I've mis-configured the system, the backup plug-in does not appear to be functioning when scheduled under the Administration -> Cron settings.

We suffered a serious failure today when the tasks table was DROPped, and a backup had not been taken by the Cron job even though it had been configured per the instructions.

This feature, per the documentation, was set up correctly.  Does it work for anyone else?

[carcam]

It's strange I can't make it works either, although if I execute the php command from the shell, the backup is created successfully.