Definitely doesn't help... but it's much better than if you had put the wrong name in your essays. In terms of impact, what probably plays a role is whether the rest of the recommendation is a complete replica of what was submitted to other schools or whether it was tailored to the correct school and the only mistake was the wrong school. If it's a complete replica of the recommendation to other schools than will hurt. If it's just a matter of the school being incorrect than that probably isn't that bad... In other words others have had that happen and still gotten in.