Having issue in modifiying Customer transparent table

Dear gurus

i have created a program which should modify transparent table from itab.

below is the code i have written

LOOP AT itab.

  itab-prior = 1.
  itab-aedtm = sy-datum.

  SELECT SINGLE kunnr INTO itab-kunnr
    FROM vbak
    WHERE vbeln = itab-kdauf.

  SELECT SINGLE vkorg vtweg spart
    INTO (vkorg, vtweg , spart)
    FROM vbak
    WHERE vbeln = itab-kdauf.

  SELECT SINGLE name1 FROM kna1
    INTO itab-name1
    WHERE kunnr = itab-kunnr.

  SELECT SINGLE fbuda INTO fbuda
  FROM vbkd
  WHERE vbeln = itab-kdauf AND
  posnr = itab-kdpos.

  itab-ddate = fbuda.

  SELECT SINGLE cuobj kwmeng INTO (cuobj , itab-kwmeng)
    FROM vbap WHERE
    vbeln = itab-kdauf AND
*    werks = itab-plant or
    vstel = itab-plant AND
    posnr = itab-kdpos AND
    abgru = space.

  CALL FUNCTION 'CUCB_GET_CONFIGURATION'
    EXPORTING
      instance                     = cuobj
    IMPORTING
      ibase                        = ibase
      configuration                = config
      eo_cbase_ref                 = cbase
    EXCEPTIONS
      invalid_input                = 1
      invalid_instance             = 2
      instance_is_a_classification = 3
      OTHERS                       = 4.

  IF sy-subrc = 0.
    LOOP AT config INTO wa_config.
      LOOP AT wa_config-values INTO wa_values.

        SELECT SINGLE atnam FROM cabn INTO charname
           WHERE atinn = wa_values-atinn AND
                 adzhl = '0000'.
        IF sy-subrc = 0.
          IF charname+0(8) = 'REELSIZE'.
            size = wa_values-atflv.
          ELSEIF charname+0(6) = 'LENGTH'.
            alength = wa_values-atflv.
          ELSEIF charname+0(9) = 'THICKNESS'.
            thickness = wa_values-atflv.
          ELSEIF charname+0(7) = 'DENSITY'.
            density = wa_values-atflv.
          ELSEIF charname+0(8) = 'CORE_DIA'.
            coredia = wa_values-atflv.
          ENDIF.
        ENDIF.
      ENDLOOP.
    ENDLOOP.
  ENDIF.
  itab-size = size.
  itab-alength = alength.
  itab-thickness = thickness.
  itab-density = density.
  itab-coredia = coredia.
  itab-psttr = itab-aedtm.
  itab-pedtr = itab-aedtm + 1.
  SELECT SINGLE untto uebto
    INTO (itab-untto , itab-uebto)
    FROM knvv
    WHERE kunnr = itab-kunnr
    AND   vkorg = vkorg
    AND   vtweg = vtweg
    AND   spart = spart.


  itab-totswt = itab-pkwmeng + ( itab-pkwmeng / itab-totwt * itab-trimwgt ).

  MOVE-CORRESPONDING itab TO zslitorders.
  MODIFY zslitorders.
  MOVE-CORRESPONDING itab TO zslitplan.
  MODIFY zslitplan.
  MODIFY itab.
ENDLOOP.

if the data in itab is having only one line item then the table ZSLITORDERS is modified but when the itab is having multiple line item the report is throwing a dump

Database error text........: "Numeric overflow for parameter/column (42)"
  Internal call code.........: "[RSQL/178/ZSLITORDERS ]"
  Please check the entries in the system log (Transaction SM21).

  If the error occures in a non-modified SAP program, you may be able to
  find an interim solution in an SAP Note.
  If you have access to SAP Notes, carry out a search with the following
  keywords:

  "DBIF_RSQL_SQL_ERROR" "CX_SY_OPEN_SQL_DB"
  "ZSNAK_PP_MANUAL_PLANNING" or "ZSNAK_PP_MANUAL_PLANNING"
  "START-OF-SELECTION"

Regards

Saad Nisar