Lengthy email error

I was "practicing" some sandy commands this weekend (trying to get the hang of @archive & forget with recurring appointments), and one of my emails was bounced with the following:

This is the Postfix program at host peach.local.

I'm sorry to have to inform you that your message could not be
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The Postfix program

<sandy@iwantsandy.com> (expanded from <[email address removed for privacy reasons]>):
Command died with status 1: " cat >
/Library/Sandy/Production/Mail/$SENDER-`/usr/bin/uuidgen`; chmod 666
/Library/Sandy/Production/Mail/*". Command output: chmod:
/Library/Sandy/Production/Mail/[email address removed for privacy reasons]-66F1668E-9CF2-4259-BD93-8F91B9287249:
No such file or directory

Final-Recipient: rfc822; sandy@iwantsandy.com
Original-Recipient: rfc822; [email address removed for privacy reasons]
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; Command died with status 1: " cat >
/Library/Sandy/Production/Mail/$SENDER-`/usr/bin/uuidgen`; chmod 666
/Library/Sandy/Production/Mail/*". Command output: chmod:
/Library/Sandy/Production/Mail/[email address removed for privacy reasons]-66F1668E-9CF2-4259-BD93-8F91B9287249:
No such file or directory

Now, the message seemed to be processed just fine anyway, although I got no message from Sandy saying so (It was a "forget" command, and the item was successfully forgotten). I haven't seen this recurr.</postmaster>