Table control is not displaying

Question

Hi All,
Is ther any thing wrong with the below code:
PROCESS BEFORE OUTPUT.
  LOOP AT it_zmonths_data WITH CONTROL tabcontrol_1000 CURSOR
                              tabcontrol_1000-current_line.
    MODULE status_1000.
  ENDLOOP.
PROCESS AFTER INPUT.
  MODULE user_command_1000.
  LOOP AT it_zmonths_data.
  ENDLOOP.
MODULE status_1000 OUTPUT.
  SET PF-STATUS 'MENU_1000'.
SET TITLEBAR 'xxx'.
  IF NOT it_months_data[] IS INITIAL.
    CLEAR:it_months_data.
    LOOP AT it_months_data.
      zmonths_data = it_months_data.
      APPEND zmonths_data.
      CLEAR zmonths_data.
    ENDLOOP.
  ENDIF.
ENDMODULE.                 " STATUS_1000  OUTPUT
MODULE user_command_1000 INPUT.
  CASE sy-ucomm.
    WHEN 'DISP'.
      break hfrmm037.
      PERFORM validate_period.
      PERFORM get_month_days_weeks.
      PERFORM get_data_from_custom_tables.
      PERFORM get_data_for_months.
      PERFORM z1000_include.
     break hfrmm037.
      IF NOT it_months_data[] IS INITIAL.
        DATA:lines TYPE sy-tabix.
        DESCRIBE TABLE it_months_data LINES lines.
      ENDIF.
      tabcontrol_1000-lines = lines.
    WHEN 'EXIT'.
      LEAVE PROGRAM.
  ENDCASE.
ENDMODULE.                 " USER_COMMAND_1000  INPUT
And the error is:
  This error is connected to the processing of an internal table with the
  field or variable "IT_ZMONTHS_DATA", and was triggered within in the program.
Please advice.
Thanks a lot.

Answer 1

it's my mistake. The table which I have defined at the screen level is the structure instead of database table or internal table.