Need an API to change the status of open PO's to FInally Closed

I am using the PO_ACTIONS.CLOSE_PO API to close the open PO's but API is faling to close the purchase orders in 11i.

Please help me on this issue.

DECLARE

x_action constant varchar2(20) := 'FINALLY CLOSE';

x_calling_mode constant varchar2(2) := 'PO';

x_conc_flag constant varchar2(1) := 'N';

x_return_code_h varchar2(100);

x_auto_close constant varchar2(1) := 'N';

x_origin_doc_id number;

x_returned boolean;

beginfnd_global.apps_initialize (user_id => 123,resp_id => 4354,resp_appl_id => 201);DBMS_OUTPUT.PUT_LINE ('Calling PO_Actions.close_po for Closing/Finally Closing PO =>' );x_returned :=po_actions.close_po(p_docid =>