plot style doesn't work

Hi, When I try to assign plotstyle to a new drawing, it can't find any ctb files (the button to add ctb is grey and not working) , although I do see that when I do plotstylefath in command line- the path is correct. I cant start a new ctb also, I get a massage that "failed to save file". In files that already had a ctb assign to them, it says "missing" but somehow still plot in that ctb.... help!!!