Cron Job Problem!!!

Hello
My hosting sent to me one mail for problem of CronJob, what is my problem?

Time: Tue Aug 20 10:31:55 2013 +0430
Account: MYUSERNAME
Resource: Process Time
Exceeded: 37854 > 1800 (seconds)
Executable: /usr/local/cpanel/bin/jailshell
Command Line: jailshell (prexin) [init] shell -c php -q /home/MYUSERNAME/public_html/WHMCSFOLDER/admin/cron.php
PID: 15706 (Parent PID:15689)
Killed: No

How can resolve it?
Thank you