Tmaranivel: Thanks guys!
I actually re-did the whole installation, partly because I couldn't find where to place the folders mentioned earlier and partly because I don't feel keen on having game-stuff installed as root.
Instead I used this method (also mentioned in vaalc4r's post):
linuxgamecast.com/2015/11/l-g-c-how-to-installing-neverwinter-nights-linux-native/
I got the game (with the haks and modules) up and running, but the movies don't play and there is no sound...at all.
If anyone feel they have the time and the energy to help me out it would be highly appreciated.
It is a bit difficult to run but here are detailed instructions to help you:
https://neverwintervault.org/forums/neverwinter-nights-1/nwn1-tutorials/linux-tutorials-installation-trouble-shooting?page=0 For the sound to work here is a ".tar.xz" file containing updated 32bit sound libraries from my own game folder that I found in my root folder and just copied over to the "lib" and "miles" folders after a lot of trial and error to make the game work in Ubuntu 18.04. Hopefully, even if the ubuntu libraries are updated in the future, the game will still run:
https://drive.google.com/open?id=1b9VkcEFNffO__0ub-rDfn2yLmOfc9kd2 For the movies:
Download and extract nwmovies-master.zip from
https://github.com/nwnlinux/nwmovies into the NWN directory.
Download the Linux BinkPlayer (the 32bit version even if linux is 64 bit) and extract it into the nwmovies folder.
If you get this error:
ERROR: NWMovies: (cookie) dlopen of libdisasm.so failed: lib/libdisasm.so: cannot open shared object file: No such file or directory.
Look for " libdisasm.so" inside nwmovies/libdis/ and copy it into the "/lib" directory in your NeverwinterNights folder. (Not needed if using my ".tar.xz" from the above link)
Hope you get it to run!