I'm a drafter and I'm working with a machinist who is using Mastercam 9. He is unable to open any of my autocad files, either dwg or dxf. He says the file opens with just a white screen if any. I've also tried saving the files as an earlier dwg and dxf version, Autcad2000, even though he says he normally can open my current version, Autocad2007. Any ideas?