You need to call a PHP file with the submited data and then check all your data there and if it checks out have it email you the document. Try something like this:
<?php
if($submit == ""){
//Put your orignal page here make sure your "sign me up"
//button looks like this
?>
<form method=post action="registration.php" ......>
<input type=submit name="submit" value="ineedporn"><?php
}
if($submit == "ineedporn"){
//Put your checking criteria here if it all checks out a line like
//this should work provided $format is already created with all
//the data you need
mail ("yourself@babesoncamera.com","$subject","$format");
//if the data is insuffecint tell your users they should be able to
//just press the back button and fill in the correct form
}
Note: If you havent set up your PHP ini file to register get values you may need to use $_GET['submit'] In place of $submit.