I may have missed this, but has anyone asked her what's going on or if she wants to be replaced? In my guild this would have been a big deal because our VP is program chairperson. I think I would want to have several members meet with her in a casual, neutral setting and ask what she wants. If she honestly says she wants to continue or resign proceed accordingly. I just hope she's honest and doesn't use the situation to manipulate you. That happened in my guild. In that case it was a committee chair and others took over critical jobs until the new year and she was not reappointed. Good luck. I just hate these very issues regarding guild life.