[ic] Not mailing orders to admin?

[Bob Puff]

Hi Gang,

I have a cart that has been running nicely for some time.  Recently, we've
seen two orders that never made it to the admin order's mailbox.  I see them
in catalog/orders, and they are in the UI.  I looked at the mail server logs,
and I see a message was sent to the person ordering, but there wasn't the
message sent to the orders_to address like usual.  I did see an error in the log:

216.231.62.34 ms2zmRm9:216.231.62.34 - [30/July/2008:17:45:08 -0400] tlistore /c
gi-bin/tlistore/ord/finalize.html Unable to send mail using /usr/sbin/sendmail

(with the message displayed after).  No errors recorded in Postfix.  Is
perhaps something getting malformed in its submission to sendmail?

Bob