Cron Job Not Working Properly

I have a slight problem with a cron job I have setup.

I wanted to save a copy of iptables every hour to a folder, so I created a script... here it is:

Code:
varDate=`date +%y%m%d`
varTime=`date +%H%M`

filename="IPtablesBackup-$varDate-$varTime"
iptables-save -c > /etc/IPtablesBackup/$filename
and called is Backup-Script.sh

Now if I just execute the script will in root ./Backup-Script.sh I get a new file with the correct filename and iptables info is saved ! Great ! So then I thought, how can I setup this automatically every hour.

Which leads me on to my problem. I inputted "crontab -e" added this line

Code:
59 * * * * /etc/IPtablesBackup/Backup-Script.sh
The problem is the script is run, I know because it creates a new file with the correct time and date, however the file is empty?

I have set Backup-Script.sh to 777 and owner and group are both root?