DXF file not working

Did you watch the video in that thread?

Make a 2D shape with either arcs or circles. Place it flat on the XY plane. Set the Camera to Parallel Projection and choose the Top standard view so the camera is looking directly down on the piece. Choose File>Export>3D Model. At the bottom of the export window set the file type to .dwg or .dxf. In the options uncheck all export entity except edges, only export edges.