Hi, just purchased Duke 3D, and can't seem to run it. When I start it up, DOSbox starts up, and a black screen pops up with text like its about to load, and then it goes back to the desktop. Im on vista if that makes a difference.

Same problem here. Neither DN3D nor DN:MP are working, and my computer has started acting odd ever since I tried to download MP, and it is the most recent change to my system. I am starting to become very unhappy with this deal, and I have never had major problems with GOG before.
Haha! I feel stupid
http://www.gog.com/en/forum/duke_nukem_series/crashing_on_startup

Um, I have this on my old windows xp PC, and it worked awesome. I installed the eduke mod and it made the game look updated and feel fully awesome.
Then I recently got a laptop that is running windows vista 64. I have the identical problem that you are experiencing. Its bothering me enough that I am considering setting up a dual-boot on the laptop. Maybe someone knows of an easy work-around instead.
-The Greg

I just bought this game, and I am having the same exact problem. I am also on Windows Vista.