Problems with piping e-mail (local delivery failed)

[philipt18]

I've set up WordPress with the Zingiri Tickets plug-in implementation of ostickets. The problem I'm having is getting an e-mail address to pipe to the ostickets pipe.php script.

I started by creating an e-mail address helpdesk@DOMAIN.

I then forward the e-mail address to:

public_html/wordpress/wp-content/plugins/zingiri-tickets/osticket/upload/api/pipe.php

which gets expanded to:

|/home1/USERNAME/public_html/wordpress/wp-content/plugins/zingiri-tickets/osticket/upload/api/pipe.php

I've made sure that pipe.php is executable (755).

I then create a ticket, which sends out an e-mail to the account's associated e-mail address.

Then I reply to the ticket, which should get piped to ostickets with the response showing up in the system. Instead I get the following message:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

pipe to |/home1/USERNAME/public_html/wordpress/wp-content/plugins/zingiri-tickets/osticket/upload/api/pipe.php
generated by helpdesk@DOMAIN
local delivery failed

Any suggestions?

Thanks.