Exchange 2007: #553 5.1.8 unable to send email - domain of sender doesn't exist

Okay. I need help on this. I believe it is a DNS issue with the message below. I am unable to send an email outbound. The error message is below. I am running Exchange 2007 and Outlook 2003 on the client.  I'm not even sure where to look. I've been at this for hours.


Diagnostic information for administrators:

Generating server: DCFINLEY.FINLEYPC.LOCAL

where-am-i@sbcglobal.net
nlpi017.prodigy.net #553 5.1.8 <cknoderer@finleypc.local>... Domain of sender address cknoderer@finleypc.local does not exist ##

Original message headers:

Received: from DCFINLEY.FINLEYPC.LOCAL ([fe80::1]) by DCFINLEY.FINLEYPC.LOCAL
 ([fe80::1%1]) with mapi; Sat, 11 Aug 2007 22:53:11 -0500
From: chris knoderer <cknoderer@finleypc.local>
To: "where-am-i@sbcglobal.net" <where-am-i@sbcglobal.net>
Date: Sat, 11 Aug 2007 22:53:09 -0500
Subject: test outbound
Thread-Topic: test outbound
Thread-Index: AcfcgPP9DP9vwPYwQXOyphrzdKUdPg==
Message-ID: <24D67CF818CAD6449283D9ED7BE81BBE056D79754A@DCFINLEY.FINLEYPC.LOCAL>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
acceptlanguage: en-US
Content-Type: multipart/alternative;
      boundary="_000_24D67CF818CAD6449283D9ED7BE81BBE056D79754ADCFINLEYFINLE_"
MIME-Version: 1.0