Here's a good read regarding the waivers and how enforceable it is with respect to sports. From the news article it looks like the players did sign a waiver but the specifics of certain conditions and where negligence could arise (bad ice) was not clear and unambiguous in wording.
http://www.recmanagement.com/feature...fid=200611gc03
She may have a case as the duty of care lies with the organizers (NHL, Patriots, NWHL etc.), and that duty was breached. The organizations' CGL (Commercial General Liability) or E&O (Errors & Omissions) policies would be the ones to respond as she tries to subrogate against them.
This would be similar to the concussion lawsuits.