Modify stmt leads dump (urgent)

PERFORM get_customer TABLES itab_futureorders.

FORM get_customer TABLES p_itab STRUCTURE itab_orders .

DATA: wa_itab LIKE LINE OF itab_orders.

SELECT a_{vbeln a}parvw

b~name1

INTO TABLE itab_customer

FROM vbpa AS a

INNER JOIN kna1 AS b ON a_{kunnr = b}kunnr

FOR ALL ENTRIES IN p_itab

WHERE vbeln EQ p_itab-soord

AND parvw EQ 'ZE'.

IF sy-subrc EQ 0.

LOOP AT itab_customer INTO wa_customer.

READ TABLE p_itab INTO wa_itab

WITH KEY soord = wa_customer-vbeln.

IF sy-subrc EQ 0.

CLEAR p_itab-name1.

p_itab-name1 = wa_customer-name1.

ELSE.

CLEAR p_itab-name1.

ENDIF.

MODIFY p_itab.

ENDLOOP.

ENDIF.

ENDFORM. " get_customer

I am getting short dump while exec the modify statement. Please let me know the error in this.

Regards,

Cheritha