Type Ultima and hit enter. The game runs fine on DOS 3.3 with PCjr Memory Options (pcjrmem) as the memory manager. It fails on DOS 5.0 with jrconfig. Further testing shows it also works on DOS 3.3 using jrconfig, but fails on DOS 5.0 with pcjrmem, so it most likely does not like DOS 5.0. Let me know if your results vary.