The thing that most amuses me about false prophets is that they very rarely possess much more Biblical knowledge than the average atheist. In this case, a Sunday School child could easily tell you that Jesus was born in Bethlehem.
Now, if the Book of Mormon was just supposed to be the word of Joseph Smith, I wouldn't care. If the book never claimed to be inerrant, it would be easy to forgive even the most ridiculous blunder. But according to Joseph Smith, "I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book". (1) Now, if the "keystone of our religion" is this book that claims to be the most correct book, through which man can get closer to God by keeping it than even the Bible can get you, I better not find a single error inside it. But I reach Alma 7:10, and I find not only a rookie mistake that even a child could correct, but also a footnote that sends me directly to proof of error!
From this fact alone, we can say that the "most correct book" is actually less correct than the Bible on which it claims to be grounded. If the keystone of your religion is so quick to refute itself, it's time for a new religion. May I now share the true Gospel with you?
References
1. Smith, Joseph - History of the Church, 4:461.