[CentOS] Postfix dropping settings CentOS4.5

My company is using Trend Micro InterScan Messaging Security Suite 7.0
for linux. This setup uses Postfix as a mail gateway for MS Exchange.
The problem I'm having is ever so often Postfix 2.2.11 will lose the
Transport mapping lookup tables setting. When this happens, mail into
our domain will stop being relayed to our Exchange server.

FYI: please remember, I'm ok with understanding how Linux works, but
I'm a Postfix noob!
Thanks in advance for the help

-- 
Johnny Massengill