I know it's an old topic but I just found out something that might be useful to anyone having problems getting this game to start.
After trying out everything, I finally got it to work by downloading the game from here:
http://www.oldgames.sk/en/game/dunge...eep/downloads/
The package also comes with a specifically pre-configured install of DosBox, tailored to run specifically DM2. But for me, it seems that it was only the bad install that was causing the errors, not my DosBox configs.
I am running the game filtered with Super2xSai engine and in windowed mode currently. Everything works like it should!