HI,
You need to do implicit enhancement.
Include LMG21FSQ
FORM Message_LOCK.
data sperr_user_name type c length 80.
select single NAME_TEXT FROM V_USR_NAME into sperr_user_name where BNAME = sperr_user.
IF sy-subrc = 01.
MESSAGE e022 WITH mara_keytab-matnr sperr_user_name RAISING lock_on_material.
EXIT.
ENDIF.