Hi,
this is the code after having modified,
but now I cannot see any dump, may be there isn't the
code which displays the output? 
*&---------------------------------------------------------------------*
*& Report ZTEXT
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*
REPORT ZTEXT.
TYPES: BEGIN OF tp_matnr,
matnr TYPE matnr,
END OF tp_matnr.
DATA:lv_matnr TYPE matnr,
t_mara TYPE TABLE OF tp_matnr,
wa_mara TYPE tp_matnr,
t_line TYPE TABLE OF tline,
wa_line TYPE tline.
SELECT-OPTIONS : s_matnr FOR lv_matnr.
START-OF-SELECTION.
SELECT matnr FROM mara INTO TABLE t_mara WHERE matnr IN s_matnr.
LOOP AT t_mara INTO wa_mara.
CALL FUNCTION 'CONVERSION_EXIT_MATN1_INPUT'
EXPORTING
input = wa_mara-matnr
IMPORTING
output = wa_mara-matnr
EXCEPTIONS
length_error = 1
OTHERS = 2.
IF sy-subrc <> 0.
* Implement suitable error handling here
ENDIF.
data:
wa_matnr TYPE THEAD-TDNAME.
wa_matnr = wa_mara-matnr.
CALL FUNCTION 'READ_TEXT'
EXPORTING
client = sy-mandt
id = 'BEST'
language = 'I'
name = wa_matnr
object = 'MATERIAL'
* ARCHIVE_HANDLE = 0
* LOCAL_CAT = ' '
* IMPORTING
* HEADER =
TABLES
lines = t_line
* EXCEPTIONS
* ID = 1
* LANGUAGE = 2
* NAME = 3
* NOT_FOUND = 4
* OBJECT = 5
* REFERENCE_CHECK = 6
* WRONG_ACCESS_TO_ARCHIVE = 7
* OTHERS = 8
.
IF sy-subrc = 0.
* use WRITE statement or use GUI_DOWNLOAD
ENDIF.
ENDLOOP.