Welcome to WebmasterWorld Guest from 220.127.116.11
Find the place where you change the settings for what should be considered spam and what shouldn't, and tell the program that email from your site should never be considered spam.
You can check that here: [postmaster.aol.com...]
Having said that since you are receiving the messages check the headers, if you or the server are using filtering software they will generally add some information in the header as to what is wrong with it.
I learned this by experience, the hard way. :-)
The DNS report will also check your SPF records and make sure you have one, and it's valid.
One of P.R.1's excellent reminders [webmasterworld.com]