PayPal IPN after upgrade

I have just upgraded from version 1.3.7 to 1.3.8a.

Admin says Zen Cart and the DB are running version 1.3.8a.

I am now in the process of testing it out fully, but I have ran into some problems. When an order is placed, the money is sent from the customers Paypal, but the customer recieves no confirmation email from us and the order does not show up in my admin.

The problem is similar to that on this post:
http://www.zen-cart.com/forum/showthread.php?t=104980

except I view ipn_main_handler.php via the browser I do get the correct: Nothing to process. Please return to home page.

Any advise would be greatly appreciated.
Thanks, Damien.

UPDATE
The problem has now been sorted. It was just my impatience, everything is working fine, there was just some sort of delay.

Thanks anyway :D