Start SSH if is not already running (Bluepanel -> Extras -> Services/Daemons)
Login with SSH to your box
Check if crontab is in place
# ls -l /bin/crontab
lrwxrwxrwx 1 root root 7 Dec 17 22:56 /bin/crontab -> busybox
Check if crond is in place
# ls -l /sbin/crond
lrwxrwxrwx 1 root...