Hey there. It is just a guide for everbody who have the same problem as I have. I have installed the game via playonlinux and wine 1.9.23.

My setting:
OS: Debian Jessie
Kernel: Backportskernel 4.7.0-0.bpo.1-amd64
Graphik: Backportsfglrx 1:15.12-2~bpo8+3
CPU: i5-6600k
RAM: 16GB

My problem:
If I start the game the game crash at the beginning. I see the nwn-logo and then I have to switch to ptty1 to "kill -9" the game. I have tested many libs and settings. With the free radeon driver the game works perfect, but not with the fglrx from the backports. I do not know why.

Solution:
Start playonlinux, select the game and click on "configuration" in the top of playonlinux. Then take the tab "Wine" and click on "wine configuration".
Sorry I have the german language and do not know how it name in english exactly.
If you are in the configuration choose the graphib tab and active the virtual desktop option and write you default desktop solution on it.
Then click on "apply".
Now you open the nwn.ini in the gamedirectory and change there the solution also.
If you want to play now you have to go to the wine configuration again and you have to move the configuration window to the right. Behind the window is the shortcut for the game and you make a double click to start the game. Now it works!!!

Now, there is perhaps another problem for you. All creatures ingame a invisible, so you go to the graphic setting ingame and uncheck the option "enable environment shadows on characters". If you unbox it you can see all creatures.
I also had the problem that I can not activate the box of "reflect water". You can activate this in the nwn.ini too.

Hope I could help anybody ;)
Wish you a nice christmas time