PROBLEM DURING UPDATE FIELD LIPS-LFIMG IN STANDARD TABLE LIPS

[suityan98]

All the flows seen like okay, however when pass through the call function, the update also failed and the field that need to be update not updated, not sure where is the problem, can someone help me with this problem? do i miss any step?

DATA: LT_PROT LIKE PROTT OCCURS 10 WITH HEADER LINE.
  DATA: LT_VBPOK  LIKE VBPOK OCCURS 500  WITH HEADER LINE.
  DATA: LS_VBKOK  LIKE VBKOK.
  DATA: GT_LIPS LIKE LT_LIPS.
  DATA: WA_LIPS TYPE LTY_LIPS.


  DATA: EF_ERROR_ANY_0                TYPE C,
        EF_ERROR_IN_ITEM_DELETION_0   TYPE C,
        EF_ERROR_IN_POD_UPDATE_0      TYPE C,
        EF_ERROR_IN_INTERFACE_0       TYPE C,
        EF_ERROR_IN_GOODS_ISSUE_0     TYPE C,
        EF_ERROR_IN_FINAL_CHECK_0     TYPE C.


  SELECT * FROM LIPS INTO CORRESPONDING FIELDS OF TABLE LT_LIPS
      WHERE VGBEL = LT_BCODE_I-VGBEL
      AND VGPOS = LT_BCODE_I-VGPOS. 

LOOP AT LT_LIPS INTO WA_LIPS.
              WA_LIPS-LFIMG = LT_BCODE_I-MENGE.
              MODIFY LT_LIPS FROM WA_LIPS INDEX SY-TABIX.
            ENDLOOP.

             "VBPOK IS CHANGE INDICATOR, AFTERWARD CALL FUNCTION TO CHANGE FIELD LFIMG IN STANDART TABLE LIPS.
             LOOP AT LT_LIPS INTO GT_LIPS.
               LT_VBPOK-LFIMG = GT_LIPS-LFIMG.
               APPEND LT_VBPOK.
             ENDLOOP.
            ls_vbkok-vbeln_vl   = LT_BCODE_I-REF_DOC.
            CALL FUNCTION 'WS_DELIVERY_UPDATE'
              EXPORTING
                vbkok_wa                    = ls_vbkok    " DELIVERY DOCUMENT NUMBER
                synchron                    = 'X'
                no_messages_update          = ' '
                update_picking              = 'X'
                commit                      = 'X'
                delivery                    = LT_BCODE_I-REF_DOC   "VARIABLE OF DELIVERY DOCUMENT
                nicht_sperren               = 'X'
                if_error_messages_send_0    = space
              IMPORTING
                ef_error_any_0              = ef_error_any_0
                ef_error_in_item_deletion_0 = ef_error_in_item_deletion_0
                ef_error_in_pod_update_0    = ef_error_in_pod_update_0
                ef_error_in_interface_0     = ef_error_in_interface_0
                ef_error_in_goods_issue_0   = ef_error_in_goods_issue_0
                ef_error_in_final_check_0   = ef_error_in_final_check_0
              TABLES
                vbpok_tab                   = lt_vbpok     "TABLE TO BE CHANGE
                prot                        = lt_prot.