Walkyra

Hi, I'm running Exile 2 on Dos Box with Windows 3.11. At first everything was running smoothly but now I'm getting these black lines as illustrated below; I've tried reinstalling the game, then even reinstalling Dos Box and Windows 3.11! It's been over 10 years since I've played Exile 2, but I seem to vaguely remember this problem occurring back then as well and I can't remember how or if I managed to solve it..