Error message "Enter payer for the Account" at Items level of opportunity

Hello All,

Good Day..!

I have an ITEMS block on the opportunity overview page.

Whenever i add a product (on the ITEMS block) and press the SAVE button of the ooportunity, i get a error messae saying " Enter Payer for the Account".

What i have done

1) I have created a new Item category by copying the Standart OPPT item cateogry,

2) The Item category Determination is maintained for the new Item category ( this is working fine)

2) The item category Partner Determination procedure for the Item is same as at the header level of the opportunity (and the procedure consists of partner functions like Dealer, Installer, specifier, sold to etc etc. And there is no partner function called payer )

Please let me know why we see the error message "Enter payer for the Account". And this message appears after i hit the SAVE button of the oppt.

Thank you..!

Regards

Karthik