I am not using OpenGL.
EDIT:
I have not noticed that steam started my game in 32 bit mode. I haven't played KSP in years, so I had no idea that would happen.
After starting it in 64bit mode, my problem has been resolved. False alarm I guess, sorry
So... I installed everything by the instruction and this happened:
Then I deleted the SSRSS folder, and the planet looks fine.
This is my GameData folder:
I hope someone can help, I'm really eager to play this mod