Windows Live Mail Beta

[krma-thkpds]

I just got an invitationa for Windows Live Beta. As I clikck to join the service the window appears telling me this;

Sorry! It looks like you can't be in the Mail beta.

This could be because
You're under 13
You have a parentally controlled account
Mail beta isn't available where you are

Does anyone know? Is Live Beta only available in U. S.? Or are there any other restrictions?

EDIT: And I don't have parenatal control.