Do you get any specific error messages?

For instance, I run a backup job like...

35 3 * * * /aixback.sh > /tmp/aixback.log 2>&1;
egrep -v "a " /tmp/aixback.log | mail
myself@mymailhost.com

This will send me an email with the results
I'm interested in from the log. Note I run
a shell script to encapsulate the backup
command since I want to do several other things
as well (gives me better control).