atd.pid

Hello, I keep getting the following failure when I shutdown/reboot:

daemon:killproc: empty pid file /var/run/atd.pid for /usr/sbin/atd failed at

In order to get rid of the message I have to do a "ps -e | grep atd" to find the pid number. Then I have to manually edit the /var/run/atd.pid file by adding the pid number to the atd.pid file. Then it shutdown/reboots ok. But, I have to repeat this process every time I reboot. I was hoping some one could tell me how to permanently fix this? Thanks in advance.