Fatal Errors after upgrade fro 1.3.9f to h

I have been trying to find the answer to this problem. After upgrading from 1.3.9f to 1.3.9h I'm getting errors when in the administrator>customer>orders and viewing orders. If I click on the Edit, Invoice and Packing Slip buttons these errors are coming up: We are not trying to change quantities only trying to change the Status and placing notes in the record and emailing the client but again can't:

[05-Jan-2011 12:30:47] PHP Fatal error: Call to undefined function zen_address_format() in /home/.../....com/catalog/admin/packingslip.php on line 97

[05-Jan-2011 12:23:16] PHP Fatal error: Call to undefined function zen_address_format() in /home/.../....com/catalog/admin/invoice.php on line 100

[05-Jan-2011 11:28:43] PHP Fatal error: Call to undefined function zen_address_format() in /home/.../....com/catalog/admin/orders.php on line 382

I'm at a loss and my client although patient is running out of patience. Can ANYONE please tell me where I might go to fix this. On top of this, I'm a relative newbie, so speak slowly and in detail if you would. I have been trying to find a solution to this since Dec 20th and I'm very discouraged.

DebbyP

You've had another thread running since 17th December in which Melanie tried to help you - and opening a completely new thread, devoid of the early information isn't going to help.

I'll post my response in your original thread.

Vger