As per the title, the game Defcon 5 by Millennium Interactive is being a little problematic. Not very often (I've been able to play through it a few times without crashes, which makes it quite hard to test), but it occasionally freezes as you navigate the VOS computer interface. Tested on 0.74, Daum, and Dosbox-X. 0.74 sometimes complains about illegal writes and/or reads, but not always.

Any ideas would be appreciated. Could it have done this on actual hardware?