email server down?

I sent an email to bikes@svbcbikes.org, and it came back with the following error.

This is the Postfix program at host sumo.dreamhost.com.

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

<bikes-svbc.dreamhost.com@lists.svbc.d...>:
[lists.svbc.dreamhost.com]: Name or service not known
Reporting-MTA: dns; sumo.dreamhost.com
X-Postfix-Queue-ID: 4B84E184DE9
X-Postfix-Sender: rfc822; pcmetz@yahoo.com
Arrival-Date: Fri, 26 Dec 2008 17:01:38 -0800 (PST)

Final-Recipient: rfc822; bikes-svbc.dreamhost.com@lists.svbc.d...
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; [lists.svbc.dreamhost.com]: Name or service not
known
</postmaster>