The letter to Wired was the main response, the 'Errors in "The Curse of Xanadu"' document was the detailed addendum to that which (I'm 98% sure) was the target

The letter to Wired was the main response, the 'Errors in "The Curse of Xanadu"' document was the detailed addendum to that which (I'm 98% sure) was the target of the now-dead http://xanadu.net/wolfsbane http://xanadu.net/wolfsbane link (yes).