Creo que debería ser asi tu sentencia:
SELECT e~kunnr e~name1 e~name2 e~stras p~ort01 e~land1 e~pstlz p~name1
INTO TABLE t_cliente_aux
FROM kna1 AS e INNER JOIN knvk AS p
ON e~kunnr = p~kunnr
INNER JOIN knvk AS p INNER JOIN knvv AS r
ON p~kunnr = r~kunnr
WHERE r~vkorg IN pi_org_ventas
AND r~spart IN pi_sector
AND e~kunnr IN pi_codigo.