I'd give that claim a LOT more credence if it had a matching track record. If there were no Actual Errors for an Actual Errors list, I'd say that was remarkable, to say the least. pfal- and all of vpw's teachings- were visibly flawed- visible unless one refuses to consider the possibility they were flawed.
For most people, that wouldn't really be a problem.
Anyone teaching can mess up (although this particular field calls for harder work at quality control than some.) It's only when someone goes around saying God Almighty was personally involved with it, so it has no errors, THAT is when the errors REALLY become an issue.