There are very few errors and if there are the only ones that I have seen or heard about are spelling like forgetting an s on word. Many, many people on SDN have used destroyer and many have attributed their success on the DAT to the use of destroyer. I would use it and not worry. If you find something that doesn't make sense look up the answer, though many times the solutions in the back will solve that problem for you, and see if it was wrong. I have yet to find a blatantly wrong answer.