The BBC has corrected Rippon's blog on three points: whether Duncroft staff knew of abuse, if there were allegations against the BBC and if women had spoken to police.
The BBC's admission that police were unaware of allegations also clashes with what Entwistle and Patten told ITV News that "we went straight to police".
Amid the fallout from the Jimmy Savile scandal the BBC is investigating nine allegations of sexual harassment among staff and contributors.
BBC boss George Entwistle has spent almost two hours taking questions from MPs about the corporation's handling of the Savile scandal.
Ex-BBC boss Mark Thompson has told ITV News he will help with any inquiry into the corporation and its handling of the Savile allegations.