Het werkt wel maar als ik bijlage opent krijg ik fout melding?

<?php 
$fileatt = "500.pdf"; // Path to the file                   
$fileatt_type = "application/octet-stream"; // File Type 
$fileatt_name = "500.pdf"; // Filename that will be used for the file as the attachment 

$email_from = "test@mijndomein.nl"; // Who the email is from 
$email_subject = "Factuur van mij"; // The Subject of the email 
$email_message = "Factuur betalen"; // Message that the email has in it 

$email_to = "test@joudomein.nl"; // Who the email is too 

$headers = "From: $email_from";   

$file = fopen($fileatt,'rb');   
$data = fread($file,filesize($fileatt));   
fclose($file);   

$semi_rand = md5(time());   
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";   
     
$headers .= "\nMIME-Version: 1.0\n" .   
            "Content-Type: multipart/mixed;\n" .   
            " boundary=\"{$mime_boundary}\"";   

$email_message = "This is a multi-part message in MIME format.\n\n" .   
                "--{$mime_boundary}\n" .   
                "Content-Type:text/html; charset=\"iso-8859-1\"\n" .   
               "Content-Transfer-Encoding: 7bit\n\n" .   
$email_message . "\n\n";   

$data = chunk_split(base64_encode($data));   

$email_message .= "--{$mime_boundary}\n" .   
                  "Content-Type: {$fileatt_type};\n" .   
                  " name=\"{$fileatt_name}\"\n" .   
                  //"Content-Disposition: attachment;\n" . 
                  //" filename=\"{$fileatt_name}\"\n" . 
                  "Content-Transfer-Encoding: base64\n\n" .   
                 $data . "\n\n" .   
                  "--{$mime_boundary}--\n";   

$ok = @mail($email_to, $email_subject, $email_message, $headers);   

if($ok) {   
echo "<font face=verdana size=2>The file was successfully sent!</font>";   
} else {   
die("Sorry but the email could not be sent. Please go back and try again!");   
}   
?> 

<?php 
$fileatt = "500.pdf"; // Path to the file                   
$fileatt_type = "application/octet-stream"; // File Type 
$fileatt_name = "500.pdf"; // Filename that will be used for the file as the attachment 
 
$email_from = "test@mijndomein.nl"; // Who the email is from 
$email_subject = "Factuur van mij"; // The Subject of the email 
$email_message = "Factuur betalen"; // Message that the email has in it 
 
$email_to = "test@joudomein.nl"; // Who the email is too 
 
$headers = "From: $email_from";   
 
$file = fopen($fileatt,'rb');   
$data = fread($file,filesize($fileatt));   
fclose($file);   
 
$semi_rand = md5(time());   
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";   
 
$headers .= "\nMIME-Version: 1.0\n" .   
            "Content-Type: multipart/mixed;\n" .   
            " boundary=\"{$mime_boundary}\"";   
 
$email_message = "This is a multi-part message in MIME format.\n\n" .   
                "--{$mime_boundary}\n" .   
                "Content-Type:text/html; charset=\"iso-8859-1\"\n" .   
               "Content-Transfer-Encoding: 7bit\n\n" .   
$email_message . "\n\n";   
 
$data = chunk_split(base64_encode($data));   
 
$email_message .= "--{$mime_boundary}\n" .   
                  "Content-Type: {$fileatt_type};\n" .   
                  " name=\"{$fileatt_name}\"\n" .   
                  //"Content-Disposition: attachment;\n" . 
                  //" filename=\"{$fileatt_name}\"\n" . 
                  "Content-Transfer-Encoding: base64\n\n" .   
                 $data . "\n\n" .   
                  "--{$mime_boundary}--\n";   
 
$ok = @mail($email_to, $email_subject, $email_message, $headers);   
 
if($ok) {   
echo "<font face=verdana size=2>The file was successfully sent!</font>";   
} else {   
die("Sorry but the email could not be sent. Please go back and try again!");   
}   
?>