and copy the included .dll file to Duke Nukem Manhattan Project's \duke\sys\ subfolder (you should replace the old .dll file located there).
The default folder path should look like this:
" C:\Program Files\GOG.com\Duke Nukem - Manhattan Project\duke\sys\duke_base.dll "
You should just replace old "duke_base.dll " for a new one .
Enjoy the game :)