Oh my! Good catch. I do believe the Catholics teach that it is the woman who crushes the serpents head. Another obvious error but that teaching would be reflected in the statue of Mary with her foot on the serpent.
Bad translation, or intentional distortion?
I'm not sure where they stand on that today...seems like some where objecting about this belief and, like other things which they eventually let go of, may have done with this as well...but it's definitely still believed by many nontheless.
....I was reading about one of the Popes who said exactly that mary would crush the serpent's head.