Error in SmartForm to PDF while Saving with Preview option.

Question

Hi,
I have created a report to convert Smartform to PDF.
I want the user to Preview data, if user is interested, then they can save the file.
When user clicks the Back button in SmartForm Print Preview, user can select the path of PDF file to save the data.
My code works fine, if Preview is disabled.
In the sub-routine createpdffile, I am getting error while creating PDF file.
The program works fine, if I disable the preview option i.e. if I uncomment
cparam-getotf = 'X'.
How can I have the both options in my report?
1)     Preview SmartForm.
2)     Save the SmartForm as PDF.
Regards,
Vikas
DATA:
  cparam TYPE ssfctrlop,
  outop TYPE ssfcompop,
*  fm_name TYPE rs38l_fnam,
*  my_tabix TYPE sy-tabix,
  file_size TYPE i,
  bin_filesize TYPE i,
  s_filename TYPE string.
DATA:
  tab_otf_data TYPE ssfcrescl,
*  tab_otf_data TYPE itcoo OCCURS 0 WITH HEADER LINE,
  pdf_tab LIKE tline OCCURS 0 WITH HEADER LINE,
  tab_otf_final TYPE itcoo OCCURS 0 WITH HEADER LINE,
  it_ekpo TYPE STANDARD TABLE OF ekpo WITH HEADER LINE.
*  it_docs  TYPE STANDARD TABLE OF docs.
START-OF-SELECTION.
  PERFORM fetchdata.
***************** suppressing the dialog box****************************
  outop-tddest = 'LP01'.
  cparam-no_dialog = 'X'.
  cparam-preview = 'X'.
*  cparam-getotf = 'X'.
END-OF-SELECTION.
  PERFORM callsmartform.
  tab_otf_final[] = tab_otf_data-otfdata[].
  PERFORM createpdffile.
  PERFORM getfilename.
  PERFORM savepdffile.
*&      Form  FetchData
FORM fetchdata .
  SELECT * FROM ekpo INTO CORRESPONDING FIELDS OF TABLE it_ekpo
  WHERE ebeln >  '4500009071' AND ebeln  < '4500009073' .
ENDFORM.                    " FetchData
*&      Form  CallSmartForm
FORM callsmartform .
  CALL FUNCTION '/1BCDWB/SF00000234'
  EXPORTING
  control_parameters         =  cparam
    output_options             = outop
    user_settings              = space
  IMPORTING
    job_output_info            = tab_otf_data
  TABLES
       t_ekpo                     = it_ekpo
* EXCEPTIONS
  IF sy-subrc <> 0.
    MESSAGE  'Error in Calling Smart Form ' TYPE 'I'.
  ENDIF.
ENDFORM.                    " CallSmartForm
*&      Form  CreatePDFFile
*       text
FORM createpdffile .
****removing the initial and final markers from the OTF data**********
*  DELETE tab_otf_data-otfdata WHERE tdprintcom = '//'.
*  READ TABLE tab_otf_final WITH KEY tdprintcom = 'EP'.
*  my_tabix = sy-tabix + 1.
******** appending the modified OTF table to the final OTF table****
* INSERT LINES OF tab_otf_data-otfdata INTO tab_otf_final INDEX my_tabix
************ converting OTF data into pdf data**************************
  CALL FUNCTION 'CONVERT_OTF'
  EXPORTING
  format = 'PDF'
  max_linewidth = 132
  IMPORTING
  bin_filesize = bin_filesize
* BIN_FILE =
  TABLES
  otf = tab_otf_final
  lines = pdf_tab
  EXCEPTIONS
  OTHERS = 5
  IF sy-subrc <> 0.
    MESSAGE  'Error in Creating PDF File ' TYPE 'I'.
  ENDIF.
ENDFORM.                    " CreatePDFFile
*&      Form  SavePDFFile
FORM savepdffile .
  CALL FUNCTION 'GUI_DOWNLOAD'
  EXPORTING
  bin_filesize = bin_filesize
  filename = s_filename
  filetype = 'BIN'
  IMPORTING
  filelength = file_size
  TABLES
  data_tab = pdf_tab
  EXCEPTIONS
  OTHERS = 22
  IF sy-subrc <> 0.
    MESSAGE  'Error in Saving PDF File ' TYPE 'I'.
  ENDIF.
ENDFORM.                    " SavePDFFile
*&      Form  GetFileName
FORM getfilename .
  DATA:
    v_name                  TYPE string,
    v_path                  TYPE string,
    v_fullpath              TYPE string,
    v_filter                TYPE string,
    v_uact                  TYPE i,
    v_guiobj                TYPE REF TO cl_gui_frontend_services.
*    v_filename              TYPE string.
  CONCATENATE 'smrt' '.pdf' INTO v_name.
  CREATE OBJECT v_guiobj.
  CALL METHOD v_guiobj->file_save_dialog
    EXPORTING
      default_extension = 'pdf'
      default_file_name = v_name
      file_filter       = v_filter
    CHANGING
      filename          = v_name
      path              = v_path
      fullpath          = v_fullpath
      user_action       = v_uact.
  IF v_uact = v_guiobj->action_cancel.
    EXIT.
  ENDIF.
  MOVE v_fullpath TO s_filename.
ENDFORM.                    " GetFileName

Answer 1

I think the excerpt and link below is the why, but the page talks about server code and not javascript.  I guessing that this is why blank pages work, but not wiki pages.  Can anyone verify this?
The following are general rules for using server-side code on a site page.
If the page is uncustomized, server-side code is supported on the page.
If the page is customized, server-side code does not run, and the page does not render. This includes the code-behind for the page itself.
http://msdn.microsoft.com/en-us/library/office/aa979592(v=office.14).aspx