just had some random crashes in the last days, don't know why

Do you have mods? If you do, then you should just re-install the game or put the old look of game back, that can cause that, atleast I think so.

I tried ciph's tune programm once, but when I it crashed the last time it wasn't running. I got a messge that a file named something like 'd3d8.dll' is not working probadly on one of the occasions Sounds like Direct3D DirectX8

it sounds like you have that demo users gaueges mod on! Ill get te link.

i have no mods at all (except skins and textures)

As what i can read in the Message a NULL address occours this error, maybe the devs forgot NULL check, i cant tell you it. The best would to catch a Debugger and take a memory snapshot and report it here.

hasn't happened again since I posted this here, I think it had something to do with LFS-Tune, maybe the sets I modified while Tune was running? I deleted them all (only the Tune ones)