Meanings of natural error in English

This is the natural error of the schools, but it is not confined to them.

A natural error on your part, for I perceived he was very gallant to you.

It is a natural error, but made in complete ignorance of the actual state of things.

But his mistake was the natural error of an ingenious man wasting his efforts on one of great directness and perfect simplicity of character.

Seeing the fellow's actions and realizing instantly the natural error that Tarzan's yellow tunic had occasioned the girl sprang between him and the soldier.

He fell into the natural error of the inexperienced teacher, that of supposing that the remedy was the ingestion of much and diversified intelligible matter.