Since it gives an authentication error... I'd say one of these scenarios:
* MSN Messenger is currently down
* You have made a typo in your e-mail address or password (remember casesensitivity!)

For Minimo, you should add: http://www.maemo.org.br/minimo/ bora user
You are probably trying to use mistral instead of bora. Also don't forget to add the herringer repository.

Assuming the application is removed, you can delete the shortcut from Extra's via the Control Panel -> Task Navigator.