Контекстная панель действий не может удалить выбранный элемент из SQLite

CAB не может удалить данные из адаптера курсора

public class History extends ListActivity{

private ReminderDB mDbHelper;
List selections = new ArrayList();
int count = 0;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.history);

    mDbHelper = new ReminderDB(this);
    mDbHelper.open();
    fillData();
    registerForContextMenu(getListView());
}

private void fillData() {
    final Cursor remindersCursor = mDbHelper.fetchAllHistoryEvents();
    startManagingCursor(remindersCursor);
    // an array for the fields to show in the list row (now only the TITLE)
    String[] from = new String[]{ReminderDB.KEY_TITLE};
    // and an array of the fields for each list row
    int[] to = new int[]{R.id.row1};
    // a simple cursor adapter and set it to display
    final HistoryCustomCursorAdapter history = new HistoryCustomCursorAdapter(this, R.layout.history_list_row, remindersCursor, from, to);
    setListAdapter(history);
    getListView().setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE_MODAL);
    getListView().setMultiChoiceModeListener(new AbsListView.MultiChoiceModeListener() {
        @Override
        public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked) {
            if(checked){
                selections.add(history.getItem(position));
                count++;
                mode.setTitle(count+ " Selected");
            }else{
                selections.remove(history.getItem(position));
                count--;
                mode.setTitle(count+ " Selected");
            }
        }

        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            MenuInflater menuInflater = getMenuInflater();
            menuInflater.inflate(R.menu.contextual_menu, menu);
            return true;
        }

        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            return false;
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            if (item.getItemId()==R.id.item_delete){
                AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
                mDbHelper.deleteHistory(info.id);
                history.notifyDataSetChanged();
                mode.finish();
            }
            fillData();
            return true;
        }

        @Override
        public void onDestroyActionMode(ActionMode mode) {
            count = 0;
            selections.clear();
        }
    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    super.onActivityResult(requestCode, resultCode, intent);
    fillData();
}
}

Это сообщение об ошибке, которое я получаю:

11-08 14:24:03.475 6934-6934/com.example.windchin.digitalbrain E/AndroidRuntime﹕ НЕИСПРАВНОЕ ИСКЛЮЧЕНИЕ: main java.lang.NullPointerException в com.example.windchin.digitalbrain.History$1.onActionItemClicked(History.java: 83) в android.widget.AbsListView$MultiChoiceModeWrapper.onActionItemClicked(AbsListView.java:7680) в com.android.internal.policy.impl.PhoneWindow$DecorView$ActionModeCallbackWrapper.onActionItemClicked(PhoneWindow.java:3299) в com.android.internal .app.ActionBarImpl$ActionModeImpl.onMenuItemSelected(ActionBarImpl.java:1009) в com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735) в com.android.internal.view.menu.MenuItemImpl.invoke (MenuItemImpl.java:152) в com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874) в com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java :630) в com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:200) в android.view.View.performClick(View.java:4475) в android.view.View$PerformClick.run( View.java:18786) в android.os.Handler.handleCallback(Handler.java:730) в android.os.Handler.dispatchMessage(Handler.java:92) в android.os.Looper.loop(Looper.java:176) ) в android.app.ActivityThread.main(ActivityThread.java:5419) в java.lang.reflect.Method.invokeNative(собственный метод) в java.lang.reflect.Method.invoke(Method.java:525) в com. android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) в com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) в dalvik.system.NativeStart.main(собственный метод)

Это класс адаптера курсора

public class HistoryCustomCursorAdapter extends SimpleCursorAdapter {
    private Context context;
    private ReminderDB mDbHelper;
    private int layout;

    public HistoryCustomCursorAdapter (Context context, int layout, Cursor c, String[] from, int[] to) {
        super(context, layout, c, from, to);
        this.context = context;
        this.layout = layout;
        mDbHelper = new ReminderDB(context);
        mDbHelper.open();
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {

        final LayoutInflater inflater = LayoutInflater.from(context);
        View rowView = inflater.inflate(layout, parent, false);

        int titleCol = cursor.getColumnIndex(ReminderDB.KEY_TITLE);
        String title = cursor.getString(titleCol);
        TextView textView1 = (TextView) rowView.findViewById(R.id.row1);
        TextView textView2 = (TextView) rowView.findViewById(R.id.row2);
        ImageView imageView = (ImageView) rowView.findViewById(R.id.icon);

        textView1.setText(title);

        String Hdate = cursor.getString(cursor.getColumnIndex(ReminderDB.KEY_DATE_TIME));
        String latitude = cursor.getString(cursor.getColumnIndex(ReminderDB.KEY_LATITUDE));
        String longitude = cursor.getString(cursor.getColumnIndex(ReminderDB.KEY_LONGITUDE));

        if(Hdate != null)
            imageView.setImageResource(R.drawable.cclock);
        else
            imageView.setImageResource(R.drawable.maps);

        if(Hdate != null)
        {
            textView2.setText(Hdate);
        }
        else
        {
            Cursor c = mDbHelper.fetchLocation(latitude, longitude);
            String location = c.getString(c.getColumnIndex(ReminderDB.KEY_LOCATION));
            int option = Integer.parseInt(cursor.getString(cursor.getColumnIndex(ReminderDB.KEY_LOCATIONOPTION)));
            String locationOption;
            if (option == 0){
                locationOption = "When I Arrive";
            } else {
                locationOption = "When I Leave";
            }
            textView2.setText(locationOption + ": " + location);
        }
        return rowView;
    }
}