Well if you missed the notification, there is something called COPPA where Amazon has to certify it doesn’t advertise to sites that market to kids under 13. If you didn’t fill out the form by October 31, they close your affiliate account and invalidate all your tags. How nice legal things are.
Oh well, so now you have to create your affiliates account and then there is the handy Better Search and Replace plugin for WordPress that let’s you change all your tags. Good luck!