Error in bsp_utilty- download

Question

I am getting an error when i call the method cl_bsp_utilty->download the coding ofr the sameis mentioned below:
CALL METHOD cl_bsp_utility=>download
EXPORTING
object_s = l_xstring
content_type = app_type
content_disposition = 'attachment;filename=webforms.xls'
response = response
navigation = navigation.
The following error text was processed in the system:
An exception with the type CX_SY_REF_IS_INITIAL occurred, but was neither handled locally, nor declared in a RAISING clause
Exception Class CX_SY_REF_IS_INITIAL
Error Name 
Program CL_BSP_UTILITY================CP
Include CL_BSP_UTILITY================CM00D
ABAP Class CL_BSP_UTILITY
Method DOWNLOAD
Line 25 
Long text An attempt was made to execute a dynamic method callon an initial(NULL-) object reference. The reference must refer to an object.
Error type: Exception
Your SAP Business Server Pages Team
can anybody tell me why am getting this error

Answer 1

Hi All,
Here is the complete code...
<%@page language="abap"%>
<%@extension name="htmlb" prefix="htmlb"%>
<htmlb:content design="design2003">
<htmlb:page title = "F4 help for Time ">
<htmlb:form>
<htmlb:button i d="submit" tex t="continue" on Cli ck="test" />
</htmlb:form>
</htmlb:page>
</htmlb:content>
In OnCreate i am filling an internal table...
DATA: ls_hours LIKE LINE OF gt_hours.
DATA: count(2) VALUE '0'.
DO 12 TIMES .
count = count + 1 .
ls_hours-hour = count .
APPEND ls_hours TO gt_hours .
CLEAR ls_hours .
ENDDO .
ls_hours-hour = '0'.
INSERT ls_hours INTO gt_hours INDEX 1.
CLEAR ls_hours .
CLEAR count.
count = '0'.
Page Attributes..
gt_hours TYPE TT_HOURS
Type Definitions..
TYPES: begin of it_hours ,
hour(2),
end of it_hours.
TYPES: tt_hours type table of it_hours.
Now is the main code of  OnInputProcessing eventhandler..
DATA: button_event TYPE REF TO cl_htmlb_event_button ,
           event TYPE REF TO if_htmlb_data.
DATA: ls_hours like line of gt_hours.
DATA: output type string ,
          l_xstring type xstring ,
           app_type type string.
event = cl_htmlb_manager=>get_event( request ).
IF event IS NOT INITIAL AND event->event_name = htmlb_events=>button .
button_event ?= event .
CASE event->event_server_name.
WHEN 'test' .
IF gt_hours IS NOT INITIAL.
LOOP AT gt_hours INTO ls_hours.
CONCATENATE
OUTPUT
ls_hours-hour
cl_abap_char_utilities=>cr_lf
INTO output SEPARATED BY space. "cl_abap_char_utilities=>horizontal_tab .
ENDLOOP.
app_type = 'APPLICATION/MSEXCEL;charset=utf-16le'.
CALL FUNCTION 'SCMS_STRING_TO_XSTRING'
EXPORTING
text = output
mimetype = 'APPLICATION/MSEXCEL;charset=utf-16le'
IMPORTING
buffer = l_xstring.
CONCATENATE cl_abap_char_utilities=>byte_order_mark_little
l_xstring
INTO l_xstring IN BYTE MODE.
CALL METHOD cl_bsp_utility=>download
EXPORTING
object_s = l_xstring
content_type = app_type
content_disposition = 'attachment;filename=webforms.xls'
response = _m_response
navigation = navigation.
endif.
ENDCASE.
ENDIF.
Regards,
Anubhav