uploaded files are corrupted

Hi, I have a script that allows the user to browse his/her local hard drive for a file and email it as an attachment. Text files come through OK but any binary type file, e.g., JPEG or PDF arrive broken. JPEG will show as a red X in my browser and Adobe will complain about the PDF. I don't know why??? A code sample of my form is: <form enctype="multipart/form-data" action="formmail.php" method="post"> Send this file: <input name="userfile" type="file"> <input type="submit" value="Send your file" name="submit"> </form> Thanks, Don