Automate snapshots in AWS

I found the thread Automating Linux EBS snapshots backup and clean-up which Sergey Romanov has given the step-by-step instruction. I tested it and works great. (Thanks, Surgey.)

However have a problem with adding cron job (last step). Got the error crond[478]: (CRON) bad command (/etc/crontab). To fix it, I added a username (root) after which the error did not appear. However, the job is still not running. Is there anything I did was wrong?

Thanks