I'm trying to get the EDuke32 to work with my copy of Duke Nukem 3D (Mac version) purchased from GOG, but it says it can't find the Duke3d.grp file. Where is it on the Mac version? I tried opening the package to find it but I had no luck in locating it.

Thank you for the help.

You'll have to go deeper and open a package inside the package you opened.

1: Right click on Duke Nukem 3D and select "Show package contents" as usual.
2: Open the folder called "Contents", then open the folder in there called "Resources"
3. You should see a file in there called "Duke Nukem 3D.boxer". Right click on it and choose "Show package contents" again.
4. Open the folder called "C.harddisk". The .GRP file is in there.

So, to recap, Duke Nukem 3D > Contents > Resources > Duke Nukem 3D.boxer > C.harddisk > DUKE3D.GRP

Hope that helps!