I cant get the quest editor work as it shuld i hawe win 10 i wich GOG team culd make it work for newer computors.

I'm guessing you're no longer interested, but for anyone else finding this thread, I have it running fine on Windows 10/x64, you just have to copy the data.mtf file from the Darkstone game directory to the Quest Editor's directory. Once it can find all the game data in there, it works great.