Having trouble with Email Piping

I am on a shared account and trying to get email piping to work, just as this person has done: http://discussion.dreamhost.com/thread-124918.html?highlight=email+piping

-I set an email filter up for catch-all@mydomain.com to forward all email to my shell account.

-My .forward.postfix file is in my home directory, and here are its contents:

-I know that my process-email.php works just fine because it runs great when I run it with the same shell account via SSH.

In short, I’ve followed this guide in combination with this guide with no success. It seems to me that the email filter is somehow not executing the process-email.php file, but I cannot figure out why. The email filter was acting pretty hairy - I tried changing it around to add a prefix to the email subject, and it worked (though it was not working consistently).

Any suggestions? Thanks.