Mail funtion question

I am using the PHP mail() function to send subscribed-to bulk email. It successfully sends emails to the valid email addresses, but I get a series of error messages at the top of the PHP page like: /home/[my folder]/dead.letter... Saved message in /home/[my folder]/dead.letter 123... User unknown I'm almost positive the error msgs are caused by invalid email addresses that are stored in the database. I have two questions: 1. How can I suppress the error msg's? @mail....? 2. Can the error be trapped and the invalid email address captured to be spit out in code? Thanks for your help. Irvin.