A server that's been in production for years started rejecting all outgoing email. Nothing has changed. Here is a snippet of a log file, any ideas would be appreciated.
2012-03-15 09:44:23.220868500 6544 Accepted connection 0/40 from 192.168.1.214 / pc-00214.osi.dyndns.org
2012-03-15 09:44:23.221016500 6544 Connection from pc-00214.osi.dyndns.org [192.168.1.214]
2012-03-15 09:44:23.223929500 6544 tls plugin (init): ciphers: ALL:!aNULL:!ADH:!eNULL:!LOW:!EXP:RC4+RSA:+HIGH:+MEDIUM
2012-03-15 09:44:23.231221500 6544 220 smeserver.osi.dyndns.org ESMTP
2012-03-15 09:44:23.236758500 6544 dispatching HELO techsupportxp
2012-03-15 09:44:23.237765500 6544 250 osi.dyndns.org Hi pc-00214.osi.dyndns.org [192.168.1.214]; I am so happy to meet you.
2012-03-15 09:44:23.238019500 6544 dispatching MAIL FROM:<alert@osi-ny.com>
2012-03-15 09:44:23.238289500 6544 full from_parameter: FROM:<alert@osi-ny.com>
2012-03-15 09:44:23.239482500 6544 getting mail from <alert@osi-ny.com>
2012-03-15 09:44:23.239544500 6544 250 <alert@osi-ny.com>, sender OK - how exciting to get mail from you!
2012-03-15 09:44:23.239786500 6544 dispatching RCPT TO:<CHRIS@KOZEL.NET>
2012-03-15 09:44:23.241165500 6544 250 <CHRIS@KOZEL.NET>, recipient ok
2012-03-15 09:44:23.241349500 6544 dispatching DATA
2012-03-15 09:44:23.241660500 6544 354 go ahead
2012-03-15 09:44:23.242416500 6544 spooling message to disk
2012-03-15 09:44:23.282647500 6544 FATAL PLUGIN ERROR [check_basicheaders]: Can't call method "get" on an undefined value at /usr/share/qpsmtpd/plugins/check_basicheaders line 49, <STDIN> line 14.
2012-03-15 09:44:23.282651500
2012-03-15 09:44:23.289510500 6544 FATAL PLUGIN ERROR [logging::logterse]: Can't call method "get" on an undefined value at /usr/share/qpsmtpd/plugins/logging/logterse line 127.
2012-03-15 09:44:23.289512500
2012-03-15 09:44:23.291057500 6547 queue::qmail_2dqueue plugin (queue): (for 6544 ) Queuing qp 6547 to /var/qmail/bin/qmail-queue
2012-03-15 09:44:23.291569500 6544 FATAL PLUGIN ERROR [queue::qmail_2dqueue]: Can't call method "print" on an undefined value at /usr/share/qpsmtpd/plugins/queue/qmail-queue line 59.
2012-03-15 09:44:23.291572500
2012-03-15 09:44:23.291895500 6544 451 Queuing declined or disabled; try again later
2012-03-15 09:44:23.292550500 6544 dispatching QUIT
2012-03-15 09:44:23.292729500 6544 221 osi.dyndns.org closing connection. Have a wonderful day.
2012-03-15 09:44:23.292795500 6544 click, disconnecting
2012-03-15 09:44:24.196719500 4669 cleaning up after 6544