sendmail error 553 and more

I've set up a linux machine to run our http and ftp services. I want it to send me emails if the drives get too full. I've installed diskcheck and sendmail to accomplish this. Unfortunately, I can't get it just right.

My configuration:
Linux 9.0
Kernal 2.4.20-31.9
Sendmail 8.12.8
Diskcheck 1.42

The problem is the email gets hung up in sendmail for 5 days and eventually gets spat out to the correct address with all the errors listed. Here they are:

------------------------------------
The original message was received at Sat, 13 Nov 2004 09:02:00 -0500
from localhost [127.0.0.1]


----- The following addresses had permanent fatal errors -----
<basic_webmaster@ncsu.edu>
(reason: 553 5.1.8 <basic_webmaster@ncsu.edu>... Domain of sender address root@Speck does not exist)


----- Transcript of session follows -----
451 Speck: Name server timeout
... while talking to mr04.ncsu.edu.:
>>> DATA
<<< 553 5.1.8 <basic_webmaster@ncsu.edu>... Domain of sender address root@Speck does not exist
550 5.1.1 <basic_webmaster@ncsu.edu>... User unknown
<<< 503 5.0.0 Need RCPT (recipient)
451 Speck: Name server timeout
451 Speck: Name server timeout
Reporting-MTA: dns; Speck
Received-From-MTA: DNS; localhost
Arrival-Date: Sat, 13 Nov 2004 09:02:00 -0500


Final-Recipient: RFC822; basic_webmaster@ncsu.edu
Action: failed
Status: 5.1.8
Remote-MTA: DNS; mr04.ncsu.edu
Diagnostic-Code: SMTP; 553 5.1.8 <basic_webmaster@ncsu.edu>... Domain of sender address root@Speck does not exist
Last-Attempt-Date: Sat, 13 Nov 2004 09:02:00 -0500
Return-Path: <root@Speck>
Received: from Speck (localhost [127.0.0.1])
by Speck (8.12.8/8.12.8) with ESMTP id iADE200m005049
for <basic_webmaster@ncsu.edu>; Sat, 13 Nov 2004 09:02:00 -0500
Received: (from root@localhost)
by Speck (8.12.8/8.12.8/Submit) id iADE20Ca005047;
Sat, 13 Nov 2004 09:02:00 -0500
-----------------------------------------

I've put my email as the receipient address in diskcheck.conf (that's basic_webmaster@ncsu.edu).

I've edited sendmail.mc with the following lines:


Other than that, I've left that file alone figuring I didn't want it to receive any emails.

Other files I've edited include the following:
/etc/mail/relay-domains
ncsu.edu
/etc/mail/virtusertable
@Speck basic_webmaster@ncsu.edu

I've used "make -C /etc/mail" to rebuild the sendmail.cf file and have stopped and restarted sendmail after each change.

I've also rebuilt the virtusertable.db with "makemap hash /etc/mail/virtusertable < /etc/mail/virtusertable".

What am I missing here?