I'm not sure why this happened by I had to reboot both Sendmail and MIMEDefang to stop this from happening.. It appeared to show up in my logs in great numbers...
================ Aug 20 08:54:46 mail mimedefang-multiplexor[6293]: Slave 2 stderr: Use of uninitialized value in numeric gt (>) at /usr/lib/perl5/site_perl/5.8.8/Mail/SpamAssassin/Locker/UnixNFSSafe.pm line 95. Use of uninitialized value in subtraction (-) at /usr/lib/perl5/site_perl/5.8.8/Mail/SpamAssassin/Locker/UnixNFSSafe.pm line 104. Aug 20 08:54:47 mail mimedefang-multiplexor[6293]: Slave 2 stderr: Use of uninitialized value in numeric gt (>) at /usr/lib/perl5/site_perl/5.8.8/Mail/SpamAssassin/Locker/UnixNFSSafe.pm line 95. Use of uninitialized value in subtraction (-) at /usr/lib/perl5/site_perl/5.8.8/Mail/SpamAssassin/Locker/UnixNFSSafe.pm line 104. =================