[CRH911S]

I think it must be determined that, in fact, a prohibited employment practice did in fact take place. Your company is protecting itself and this is routine treatment in dealing with disgruntled employees.
Based on what I've read here there doesn't appear to be a prohibited employment practice taking place. Did she report this to your superior? Did she ask you to stop whatever behavior your being accused of? And the list goes on and on.
Fact of the matter is, by not taking appropriate action this can be percieved by the employee that their behavior and/or performance is acceptable. I would continue with the progressive discipline but first let her know what is and what isn't acceptable. Give her time to improve. And if this doesn't do the trick bring her in for a day-in-court. You must have the proof and must let her know what rule or regulation is that she is accused of violating. Give her the opportunity to give her side of the story. Also, it's important for her to have a representative present during the interview...for obvious reasons. If discipline is warranted, issue it. Just make sure the discipline is reasonably related to the infraction. Avoid desperate disciplane and make sure it's equitable.
Now, quit whining and enjoy you day off!