A problem with duke nukem II

OS Win7 home with DOSBOX for my MSDOS games.I just got done reinstalling
Duke nukem II on my laptop after I had to do a partition wipe and
reinstalled everything including the Win7 os on my laptop because some
garbage got deposited on my C: hard drive. After the reinstall. Duke
Nukem II was working just fine starting at episode 1 level 1 all the way
up to episode 3 level 2. E3 L2 played fine but when I exited E3 L2,
instead of E3 L3 starting I had a white box were the level should be.
The game borders were still there but I was completely locked out of the
game. I had to completely shut down DOSBOX to get out of the game. What
happened?

Steve