postfix + osCommerce problem

[Thomas Jollans <tjollans@jollybox.de>]

I am creating an osCommerce-based webshop and am having probems with 
postfix. the mail below gets returned by the mailer. (things in square 
brackets were left because they are unimportant and/or to protect my and 
other's privacy. [EMAIL ADDRESS] signifies a proper and existant email 
address) I do not understand this problem because the recieptent *is* 
specified.

> [HEADER ETC]
>
> This is the Postfix program at host localhost.localdomain.
>
> 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
>
> <unknown>: No recipients specified
>
> --4632943DF.1133890478/localhost.localdomain
> Content-Description: Delivery report
> Content-Type: message/delivery-status
>
> Reporting-MTA: dns; localhost.localdomain
> X-Postfix-Queue-ID: 4632943DF
> X-Postfix-Sender: rfc822; www-data@localhost.localdomain
> Arrival-Date: Tue,  6 Dec 2005 18:34:38 +0100 (CET)
>
> Final-Recipient: rfc822; unknown
> Action: failed
> Status: 5.0.0
> Diagnostic-Code: X-Postfix; No recipients specified
>
> --4632943DF.1133890478/localhost.localdomain
> Content-Description: Undelivered Message
> Content-Type: message/rfc822
>
> Received: by localhost.localdomain (Postfix, from userid 33)
>         id 4632943DF; Tue,  6 Dec 2005 18:34:38 +0100 (CET)
> To: [EMAIL ADDRESS]
> Subject: Bestellung
> From: "[OWNER NAME]" <tjollans@jollybox.de>
> To: "[CUSTOMER NAME]" <[EMAIL ADDRESS]>
> MIME-Version: 1.0
> X-Mailer: osCommerce Mailer
> Content-Type: text/plain; charset="iso-8859-1"
> Content-Transfer-Encoding: 7bit
> Message-Id: <20051206173438.4632943DF@localhost.localdomain>
> Date: Tue,  6 Dec 2005 18:34:38 +0100 (CET)
>
> [MESSAGE ETC]


Thomas Jollans