it has to be the full OS path, not a relative path.
where is the pem file located in relation to the confirm page?
your code:
realpath("../linkpoint/number.pem")
is moving down one directory from the confirm page to look for the linkpoint folder. is this correct?
what if you use:
<?php echo("Confirm Path: ".realpath("confirm.php").""); ?>
what does that return?