Some MS-DOS programs, such as those using the extender library that SnowBro's programs use, don't cooperate well with Windows NT's DOS box. (Windows 2000 is NT 5.0, Windows XP is NT 5.1, and Windows Vista is NT 6.0.) For NT, you need a Win32 native nametable editor. Luckily, I've made 8name, part of Pin Eight NES Tools.