Comment 2 for bug 303086

  To the best of my knowledge, the output option "Save as DXF (Autocad)". is no longer supported. It will call a shell file called ps2dxf.sh which will crash with a GLib:SpawnError.
  The option "Desktop Cutting Plotter" should produce an output. Before using this option you should first choose the menu item "Edit | Select All",
and then choose the menu item "Path | Object to Path". This will convert the drawing into a standard form that should give a more consistent result.
   Let me know if this does not work for you; this output has been modified since the release of Inkscape 0.46, see for example Bug 192923