The error seems to arise only when the Yahoo trace system is busy forwarding the identity of an account holder to the lists maintained by the Office of the U.S. Attorney General when an enormous load of pornography is constantly being requested to be funneled through a mailbox by a user. It's a pseudoerror condition used by the system to keep the user busy and visiting the site to autenticate the evidence they need in certain states and territories for prosecution. It usually goes away within 24 hours. No biggie.