dump while calling an action of a button on a pop up window

Hello All,

I am developing a web dynpro component, in my web dynpro component I have two views. On the first view I have a button that calls the second view and for this I have written the following code:

lo_api_component  = wd_comp_controller->wd_get_api( ).
  lo_window_manager = lo_api_component->get_window_manager( ).
  lo_window         = lo_window_manager->create_window(
                     window_name            = 'ZWD_SCREEN'
*                    title                  =
*                    close_in_any_case      = abap_true
                     message_display_mode   = if_wd_window=>co_msg_display_mode_selected
*                    close_button           = abap_true
                     button_kind            = if_wd_window=>CO_BUTTONS_CLOSE
                     message_type           = if_wd_window=>co_msg_type_none
*                     default_button         = if_wd_window=>CO_BUTTONS_CLOSE
                     ).
  lo_window->open( ).

the above code is working fine and it's launching the second view correctly. Now I wanted to put some logic when a user clicks on button CLOSE and for this I have written the below code:

CALL METHOD lo_window->subscribe_to_button_event
    EXPORTING
      button            = if_wd_window=>CO_BUTTONS_CLOSE
*      button_text       =
*      tooltip           =
      action_name       = 'CLOSE'
      action_view       = l_api.
*      is_default_button = ABAP_FALSE

I have created an action 'CLOSE' and put my logic in the method ONACTIONCLOSE, but I am getting the below dump "but when I add an action to the CLOSE button I am getting this dump "No Button 2 Is Defined for Popup ZHWD_SCREEN ""

Can you please let me know what am I doing wrong here?

Thanks.,

Rajat