PayPal IPN - purchase description HELP!

I am trying to customize my PayPal IPN - and when a customer gets to the PayPal screen to begin payment, the following lines of code appear in the table beneath my store's header, under "Description" in the table:

MODULE_PAYMENT_PAYPAL_PURCHASE_DESCRIPTION_TITLE

Item # MODULE_PAYMENT_PAYPAL_PURCHASE_DESCRIPTION_ITEMNUM

(the other fields in the table are fine, such as Unit Price, Quantity, and Amount).

Clearly, I need to define something here, but where do I go to do this for both of these lines of code?

Thank you for your help!
Katie

My Paypal IPN works fine and I didn't have to alter the code at all. From other comments here, I suspect some files were corrupted in uploading. My guess would be to re-upload /includes/modules/payment/paypal and see if that helps. If not, say so here and hopefully one of the gurus will jump in.

mamasylvia's comments are correct - - One should not be "mucking" around in that file at all...

For errors in Paypal, take a look at :

http://www.zen-cart.com/forum/showthread.php?t=127668&highlight=MODULE_PAYMENT_PAYPAL_PURCHASE_DESCRIPTION_TITLE

It's possibly because of a spelling error

What I did:

• See if what is shown on the Paypal page is the same as on line 59, if not then copy from paypal, and replace the one in paypal.php