Excel upload/Download facility in oracle forms is not working

Question

During excel download/upload activity from oracle forms 10G/11G application , we encountered with below messages.

"Microsoft office excel cannot open or save any more documents because there is not enough available memory or disk space.
To make more memory available, close workbooks or programs you no longer need. To free disk space, delete files you no longer needed."

We can see the excel session been created in server.

Note:-Below code is perfectly working in develop environment ,but not working in customers place.

  -- Start Excel
   application:=OLE2.CREATE_OBJ('Excel.Application');
   -- OLE2.SET_PROPERTY(application, 'Visible', 'True');
   -- Return object handle to the Workbooks collection
   workbooks:=OLE2.GET_OBJ_PROPERTY(application, 'Workbooks');
   -- Add a new Workbook object to the Workbooks collection
   workbook:=OLE2.GET_OBJ_PROPERTY(workbooks,'Add');
   -- Return object handle to the Worksheets collection for the Workbook
   worksheets:=OLE2.GET_OBJ_PROPERTY(workbook, 'Worksheets');
   -- Get the first Worksheet in the Worksheets collection
   -- worksheet:=OLE2.GET_OBJ_PROPERTY(worksheets,'Add');
   args:=OLE2.CREATE_ARGLIST;
   OLE2.ADD_ARG(args, 1);
   worksheet:=OLE2.GET_OBJ_PROPERTY(worksheets,'Item',args);
   OLE2.DESTROY_ARGLIST(args);
 OPEN  c_round_off_rules;
 FETCH c_round_off_rules INTO v_round_off_rules;
 CLOSE  c_round_off_rules; 

BEGIN
  SELECT x_company_name
     INTO v_company_name
     FROM gem01_company
     WHERE c_company_cd = :GLOBAL.COMPANY_CODE;
EXCEPTION WHEN OTHERS THEN
 v_company_name := ' ';
END;           

   --Here data will be loaded into excel file.

  -----TILL HERE--
    --message('autofit columns');
    -- Autofit columns and rows
    range := OLE2.GET_OBJ_PROPERTY( worksheet,'UsedRange');
    range_col := OLE2.GET_OBJ_PROPERTY( range,'Columns');
    OLE2.INVOKE( range_col,'AutoFit' ); 
    OLE2.RELEASE_OBJ( range );
    OLE2.RELEASE_OBJ( range_col );
    -- create a file on server location ----
    --message('create file');
    v_as_file:= WEBUTIL_FILE_TRANSFER.Get_Work_Area ||userenv('SESSIONID') || '.xls';

    --message('create arguments');
    args := OLE2.CREATE_ARGLIST;
    OLE2.ADD_ARG( args, v_as_file );
    OLE2.INVOKE( worksheet,'SaveAs',args );
    OLE2.DESTROY_ARGLIST( args );

  -- message('application close');
    -- Quit application
    OLE2.INVOKE( workbook ,'Close');
    OLE2.INVOKE(application,'Quit');
  --  message('application quit');

    -- Release the OLE objects
    OLE2.RELEASE_OBJ(worksheet);
    OLE2.RELEASE_OBJ(worksheets);
    OLE2.RELEASE_OBJ(workbook);
    OLE2.RELEASE_OBJ(workbooks);
    OLE2.RELEASE_OBJ(application); 
--message('object rleased');
    p_filename := client_get_file_name('C:\', file_filter=>'Excel files (*.xls)|*.xls|', dialog_type=>save_file)||'.xls' ;
   --message(p_filename);
    --message('get file location');
--:file_name :=p_filename;
  -- Transfer the file to given Path ----- 
    v_trf_stat := WEBUTIL_FILE_TRANSFER.AS_To_Client_With_Progress(p_filename, v_as_file,
         'PentaFinancial','File Transfer from Application Server');   
    --message('file transfered at new location');

   IF v_trf_stat THEN

        SET_APPLICATION_PROPERTY(CURSOR_STYLE,'DEFAULT');
      synchronize;
      message('Writing to excel file complete.');   
      message(' ',no_acknowledge);
      --
    ELSE
      synchronize;
      message('Writing to excel file incomplete.');     
      message(' ',no_acknowledge);
      --        
    END IF;

   -- Focus to the original location
   go_block(cur_block);
   go_record(cur_record);
   go_item(cur_block||'.'||cur_item);


   HOST('DEL ' || v_as_file,screen);

END;