You can use same weapon on all subclasses, you can't change it.
It is better because for Olympiad hero you can return hero weapon only because not everyone is following server modifications and they don't know that hero weapon is only for main class.
If you are trying to dual box or you share same IP with someone else on boss zone or your character don't have valid ID you will be moved out.
Otherwise it's possible that you was teleported out because of Antharas event.
It may look like that because when players are newbies they have better chance to get all kind of rewards.
Right now for newbies this chance is slightly reduced but it is still better then for non newbie players.