How can I tell the reason of failure for a script executed via cron job?

On my linux box I have the typical /etc/cron.hourly directory with scripts. I created one with the following simple code to run a ruby script:

#!/bin/bash

ruby /home/eltony/data_warehouse_scripts/import.rb

While I can look at /var/log/cron.log and verify the hourly cron is running, the script never executes. I'm not sure exactly why, but I am sure that when I type that command into my CLI and hit enter, the script runs and does what it should.

I'm not really sure how to debug this issue so any help would be great. The permissions seem fine because they are the same as all of the scripts in cron.hourly and cron.monthly:

-rwxr-xr-x   1 root root    65 Jun  3 12:53 le_warehouse_sync
-rwxr-xr-x   1 root root   268 Nov  9  2009 mcelog.cron

Thanks!