Well, the usage of real mode features in a 16-bit Windows programm was never considered good style, using the DOS binary with dosbox&Co seems much more reasonable. Windows has a lot of backwards compatibility hacks incorporated, even some application-specific ones. There should be newer versions, Visual dBase 7.5 (old 32-bit) or dBase plus 2.70 (very recent), if you can get hold of them, try them.
