I've got a PHP script that submits information from a form into a SQL database and then sends 2 MIME formatted emails using PEAR to a few specific email addresses and the email of the person submitting the form.

I'm having issues with it consistently emailing the form to the primary recipients and only sending the "return" email to the person who submitted the form. I've done a small amount of testing and it seems that if I submit the form and then wait a few minutes to submit the next form, it doesn't always fail (although it has failed a few times in that scenario).

I've tried running the PHP script in PHP4 and PHP5 and get the same result. Does anyone have any ideas as to what may cause this issue? Is it something related to mod_security or something along those lines? Or maybe a problem with my script?

I appreciate any help in this matter!