I've found out that the username i was trying to register was taken and using a different one solved the problem (anyway it would be nice that the error explains that).
Now i have another problem: When i connect to the game, and choose a faction, i have like 1 minutos before being redirect to the menu screen and while on that minute, i can do quests but cant use the chat... so no multiplayer for me

I will start a new thread for this