This is a standard cPanel host with a slightly custom cPanel interface.
Follow the standard cPanel installation as shown in the arpReach online manual.
Use the standard cPanel cron definition:
php-cli /path/to/your/public_html/a/a.php cli/auto
php-cli /home/mylogin/public_html/a/a.php cli/auto
Local SMTP sending is not available on all HostGator plans.
This host does not have email catch-all functionality.
This means that incoming emailed subscriptions will only work if you set up an email forwarder (for each autoresponder) in cPanel that will automatically forward messages sent to the autoresponder's subscribe email address to your arpReach mailbox (the mailbox you’ve set in Setup / System Settings / System / Incoming email).