crontab files location

The directory where the cron daemon will look for
/var/spool/cron/crontabs/{username}
Note: Do not edit directly. Needs root login for editing. Always use crontab -e
/usr/lib/cron/cron.allow - if file exists, username to be added, for user to use crontab
/usr/lib/cron/cron.deny - - if file exists, username if present will block user from using crontab

See Man Page>>

The following error condition encountered. How to correct?

-bash-3.00$ crontab -e
sh: /bin/vics: not found
The crontab file was not changed.

Set the following environment parameter to vi (if required provide complete path)
export VISUAL='vi'

The following also gives the same effect.
export EDITOR='vi'