Are you legally obligated to turn them in? NO. Are you potentially sheltering a fugitive and subject to having an Obstruction of Justice or Hindering Apprehension charge filed against you? YES. The best alternative for you to help is to assist her in getting the warrant lifted and the fine paid. For this, she should consult with an experienced criminal defense lawyer to see what the alternatives are to accopmplish this without her having to surrender herself and get incarcerated. This type of resolution has a better chance of avoiding incaceration then waiting for her to get record-checked and arrsted on the warrant. Good luck.
This response does not constitute legal advice. Given the nature of this website, it does not create an attorney-client relationship. This answer is provided solely for informational purposes, for you to use as a starting point when speaking directly with a lawyer in your State. I urge you to immediately contact an experienced criminal defense lawyer admitted to practice law in your State before you make any decisions about this case.