She was tricked into pleading guilty thinking it would get her off in return for testimony against Slobo, Karadzic and Mladic and life in comfortable exile. The Kangaroo Court betrayed her and said for appearances she would do jail time (it is a show trail after all).
Feeling betrayed thus she is refusing to testify against anyone else. She figures a jail cell is better than living poor and hated back home. At least now she has food and shelter and free medical care for what is left of her life.