Ponchaud's book was not full of errors, it was based on accounts that were (at the time) unverifiable and Chomsky went on to question their credibility.

For an outline of the points brought forth, you may read this: http://www.paulbogdanor.com/chomsky/wma.html

What the article you linked refers to as "full of errors" was in fact a review of the book by Jean Lacouture.