getting asterisk in UOM field and getting errror internal unit 000

hi to all experts.

getting asterisk in the alv output and smartform for the field UOM

SELECT  b~menge
          a~mblnr
          b~bwart
          b~matnr
          b~meins
          b~werks
          b~lgort
          b~ebeln
          b~lifnr
          a~bldat
          a~budat
          a~usnam
          a~xblnr
  INTO CORRESPONDING
    FIELDS OF TABLE it_data
  FROM    mkpf AS a
  INNER JOIN  mseg AS b ON
        a~mblnr = b~mblnr
    AND a~mjahr = b~mjahr
  WHERE  a~mblnr  IN so_mblnr
  AND    b~bwart  IN so_bwart
  AND    a~bldat  IN so_bldat
  AND    a~budat  IN so_budat
  AND    b~matnr  IN so_matnr
  AND    b~werks  IN so_werks
  AND    b~lgort  IN so_lgort
  AND    b~lifnr  IN so_lifnr
  AND    a~xblnr  IN so_xblnr.

and fieldcat

wa_fieldcat-col_pos = 9.

wa_fieldcat-fieldname = 'MEINS'.

wa_fieldcat-tabname = 'IT_OUTPUT'.

wa_fieldcat-seltext_m = 'BASE UNIT OF MEASUREMENT'.

wa_fieldcat-ref_tabname = 'T006'.

wa_fieldcat-outputlen = '3'.

APPEND wa_fieldcat TO it_fieldcat.

CLEAR wa_fieldcat.