Yahoo gives out free e-mail addresses, and therefore cannot be used to register for SWC. Try using your ISP e-mail. If it used primarily by another family member, reassure them that they need only get 1 e-mail for the initial registration, and then you can change it to a preferred e-mail for you to get anything else from SWC.
____________"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Only fools and children dream of heroes.