What error?
The fantasies about Mary that the Catholic church teach as true are complete fabrications with NO support from the word of God, which we know is truth.
The only error is the lies spread about Mary, her life, her looks, her sinlessness, her deification, and her elevation to the position of Queen of Heaven.
the error to which I am referring is to reject what the Church has to say about the blessed Virgin Mary, Mother of God, Queen of Heaven, self-identified:”I am the Immaculate Conception” (Our Lady of Lourdes), etc., etc., etc....
Say what you will, but Catholics duly behold, and have come to know extremely well, our mother (and yours).