gtk_box_pack_start: assertion `GTK_IS_BOX (box)' failed

["Divya yadav" <divyayadav gtk gmail com>]

Hello everyone..

I am trying the foolowing code but its giving warning  saying.. Please where
am I going wrong


(<unknown>:1344): Gtk-CRITICAL **: gtk_box_pack_start: assertion `GTK_IS_BOX
(box)' failed

(<unknown>:1344): Gtk-CRITICAL **: gtk_box_pack_start: assertion `GTK_IS_BOX
(box)' failed

(<unknown>:1344): Gtk-CRITICAL **: gtk_box_pack_start: assertion `GTK_IS_BOX
(box)' failed


gboolean
app_create_progress_window(bt_app_ui_state_t* this, bt_int8_t*
progress_window_title, bt_int8_t* file_name)
{
 gint     response, width, height;


 if(this->progress_window != NULL)
 {
  // progress bar window was not destroyed properly last time
  bt_app_destroy_progress_window(this);
 }

 // create a dialog box
 this->progress_window = gtk_dialog_new(progress_window_title);

 // Add label only if file_name exists. otherwise, skip this widget
 if(file_name != NULL)
 {
  GtkWidget*  file_name_label;

  file_name_label = gtk_label_new (file_name);

  gtk_misc_set_alignment (GTK_MISC (file_name_label), 0, 0.5);

  gtk_box_pack_start (GTK_BOX (GTK_DIALOG
(this->progress_window)->action_area),file_name_label, FALSE, FALSE, 0);
  gtk_widget_show (file_name_label);

  gtk_dialog_add_widget ((GtkDialog
*)this->progress_window,file_name_label);


 }

 // Add percentage counter
 this->progress_counter = gtk_label_new ("0%");
 gtk_misc_set_alignment (GTK_MISC (this->progress_counter), 1, 0);
 gtk_box_pack_start (GTK_BOX (GTK_DIALOG
(this->progress_window)->action_area),this->progress_counter, FALSE, FALSE,
0);
 gtk_widget_show (this->progress_counter);
 gtk_dialog_add_widget ((GtkDialog
*)this->progress_window,this->progress_counter);


 // Add progressbar to dialog box
 this->progress_bar = gtk_progress_bar_new ();
 gtk_widget_set_size_request (GTK_WIDGET (this->progress_bar), -1, 10);
 gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (this->progress_bar), 0);
 gtk_box_pack_start (GTK_BOX (GTK_DIALOG
(this->progress_window)->action_area),this->progress_bar, FALSE, FALSE, 0);
 gtk_widget_show (this->progress_bar);

 gtk_dialog_add_widget ((GtkDialog
*)this->progress_window,this->progress_bar);

 if(this->progress_window == NULL)
 {
  // window doesn't exist. nothing to show
  return FALSE;
 }

 // window was created. just show the window
 gtk_window_get_size(GTK_WINDOW(this->progress_window), &width, &height);
 gtk_window_move(GTK_WINDOW(this->progress_window), 0,
BT_MAIN_LCD_H-height);
 gtk_window_activate_default(GTK_WINDOW(this->progress_window));
 gtk_window_present(GTK_WINDOW(this->progress_window));


return TRUE;
}