What does this mean?

[sks1024]

I have a form mail script that sends out an email to everyone in a table in my db with variables passed from the previous pages' form.

The script seems to work fine but on the output page thats says your mail has been sent it also now displays this message which I have never seen

/home/u4/firstcrack/dead.letter... Saved message in /home/u4/firstcrack/dead.letter

Could someone tell me what this means and if I should be concerned?

Thanks

[spcomputing_com]

unfortunately its bad news. it means that the email could not be sent for one or more reasons and so the email you attempted to send has been saved as that file. open up the file using notepad etc and see if any diagnostic information is supplied.

[sks1024]

well the email did go trough because 2 of the emails on the lists are mine and I received it in both accounts.

???