FA errata to me are a very smart business strategy. Errors in every year's first aid are one of the reasons that students buy new first aid every year. If the 2011 year first aid didnt have errors, then why should a student studying for step in 2012 buy the 2012 edition, while they can get the 2011 edition for half the price? This is just my idea of the errata, because there is no other reason for first aid to have the crazy amount of errors that it does have every year. And most errors are the same from previous years editions...
Edit: This is partly why most people recommend that you stick with the first aid with all your notes that you bought from your first semester of med school, and not buy new editions.