Chkrootkit Emails Are Blank

[webcreature]

I found a tutorial online to configure cron to send emails from chkrootkit. It sends the emails, but they are blank. I can run the cron script from command line and the emails are not blank. Can't figure out what I am doing wrong.
Ideas anyone?

Here's the cron poop:

#!/bin/bash
cd chkrootkit*
./ifpromisc | mail -s "ifpromisc output" my email address here
./chkproc | mail -s "chkproc output" my email address here
./chkrootkit -q | mail -s "chkrootkit output" my email address here

Thanks!