Hi,
had the same problem with corrupt pdf downloads and solved it this way.
In the file “helper.php” I added the following two lines just above the “echo” statement.
$thepath = parse_url($fullpath);
$fullpath = ‘/home/MY_DOMAIN/public_html’.$thepath;
You would of course have to use your real domain name instead of “MY_DOMAIN” and also modify the filepath as needed.