Nothing specific that I can think of! There are some posts I might disagree with, but I don't think there are any systematic errors being made.¹ I agree with the conclusions laid out in most of the posts here, and with Mr. Yudkowsky's posts in particular. It's just easy to become so enthusiastic about becoming rational "the LessWrong way" that you end up losing that rationality! But this is not so easy as it might be with other topics, perhaps.
¹(An example of a post of Eliezer's that contains some things I disagree with would be "Circular Altruism"; I posted my views and some counter-examples there, so I won't go into it here. However, I recognize many people do agree with him, so I'm not claiming to be entirely certain his conclusions are wrong - my point is just that it's a rare individual who never arrives at an incorrect conclusion!)