It looks like you had visited the site before using your son's referral code.  The referral system is intended for users that have never been on the site before so as to prevent outright fraud.  Please don't mistake that to be an accusation that you were trying to do something wrong, but we have heard of other sites that lost their shirts because their referrals ate up all the operating capital because everyone went to the site, liked it, signed up as a referral host and then used their own referral link to access the site, essentially double dipping.