Scheduled tasks are not executing

I added a scheduled task like this:

configure
set system task-scheduler task uptime_monitor executable path /config/uptime_monitor.sh
set system task-scheduler task uptime_monitor interval 1m
save
commit
exit

I can see it was added to /etc/cron.d/vyatta-crontab:

### Added by /opt/vyatta/sbin/vyatta-update-crontab.pl ###
*/1 * * * * root /config/uptime_monitor.sh

However it is not being executed. I also tried restarting cron with "service cron restart", however that did not ifx the problem.

The file has the following permissions:

# ls -l /config/uptime_monitor.sh
-rwxr-xr-x 1 root vyattacf 6858 Aug 8 19:03 /config/uptime_monitor.sh

Any ideas?