The only thing wrong is his timetable and references to the flood. It's a common mistake yet is still inline with what is commonly taught for Christians. The Great Flood is today called the Younger Dryas Event. It is recorded in multiple cultures and the geological record. Regardless, the document is correct in that the Nephilim, and therefore the line of Cain, persist post-flood. The bible plainly says this yet many Christians are directly taught contrary to this - contradicting the bible. Moses' scouts directly report the discovery of a land controlled by giants (Nephilim) and therefore they will not go there because they eat humans. I don't fault the author for their error. Other than that it looks pretty good to me.