cronjob doesn't run???

[Timothy Smith]

i have an odd problem with this cronjob,

#!/bin/sh
cd /home/timothy
burncd -f /dev/acd0c blank
tar -zcvf  ./burning/thunderbird.tar.gz ./.thunderbird/*
tar -zcvf ./burning/Projects.tar.gz ./Projects/*
tar -zcvf ./burning/cvsd.tar.gz /usr/local/cvsd/*
mkisofs -L -l -relaxed-filenames -o tmp.iso burning
burncd -e -f /dev/acd0c data tmp.iso
rm tmp.iso
rm burning/*


n# ls -l /etc/periodic/daily/Backup
-rwxr-xr-x  1 root  wheel  323 Dec 27 22:42 /etc/periodic/daily/Backup

as you can see it's not a permissions issue. the job must do something, 
because i end up with a cdrw i can't mount :\