Android : java.lang.IllegalStateException even updating from UI thread through broadcast

I wanna understand why im getting this error and my app crashes, cause im using notifyDataSetChanged correctly from main ui thread through broadcast.

10-24 14:13:36.563: E/AndroidRuntime(24830): java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread. Make sure your adapter calls notifyDataSetChanged() when its content changes. [in ListView(2131099732, class android.widget.ListView) with Adapter(class com.example.irclient2.adapter.ConversaAdapter)]

When i receive a message (and i need to update the ui about it), i send a broadcast for it after adding the message to the data set;

public void receiveChannelUserMessage(User user, String msg,
        CategoriaMSG category) {

            // creates the message
    Mensagem mensagem = new Mensagem(user.createSnapshot(),
            Colors.removeFormattingAndColors(msg), category, nickcolor);

            // add the message
    canalConversa.addMessage(mensagem);

            // inform UI from broadcast
    Intent it = new Intent(ChatFragment.ACTION_CONVERSASETCHANGED);
    it.addCategory(MyService.CANAL);
    LocalBroadcastManager.getInstance(MyService.this).sendBroadcast(it);

}

This is the receiver in the fragment where the listview is in:

private BroadcastReceiver BR_notifyData = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        if (listview != null) {
            ((ConversaAdapter) listview.getAdapter())
                    .notifyDataSetChanged();
        }
    }
};

The receiver is registered at onResume() and unregistered at onPause(); What shoud i do about all of it? Thanks in advance.