 This phase I trial is studying the side effects and best dose of veliparib when given together with topotecan hydrochloride with or without carboplatin in treating patients with relapsed or refractory acute leukemia, high-risk myelodysplasia, or aggressive myeloproliferative disorders. Veliparib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as topotecan hydrochloride and carboplatin, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Giving veliparib together with topotecan hydrochloride and carboplatin may kill more cancer cells. 