Quote from phantazm11About the spots...there could be a light buried somewhere in that brush. I've had that error, but it has been a long time and I can't quite remember the cause.
Also...if you edit the shader, make sure you copy the shader into your own shader file or you run the risk of ruining other shaders in the game.
I think I added it right, made a .shader file in the 'scripts' folder and wrote it into the shaderlist.txt