Backups are not running

hey guys i'm using Moodle2.7+ (Build: 20140529)

I'm having major issues with the automated course backups, doesn't matter what time and date i've schedule it to run the backups won't run.

I've checkd the server and the /admin/cron.php is running fine:

Server Time: Tue, 22 Jul 2014 14:36:51 +1000Cron script completed correctly
Cron completed at 14:36:51. Memory used 15.6MB.
Execution took 0.0056269999999999 seconds

i don't see any files being created on /moodledata/temp/backup

and the time stamps under /report/backups/index.php doesn't change...

no errors in any error logs.

however if i run a backup manually it works fine.

can someone help?

cheers,

dan