Registration form never gets validated

[nukeador]

Currently the registration form always return to the form, it seems it never gets validated but no error message is displayed.

https://eventos.mozilla-hispano.org/28/prueba-colas/registration/
https://github.com/mozillahispano/mozevents/blob/master/events/views.py#L58

Ideas on how to debug it?

Ping @peregrinogris @sveggiani