I've forwarded the bug report and the dxf to upstream, along with a patch that I believe fixes the problem. I'll release a bugfix version of the debian package soon.
-- Sebastian Kuzminsky
Thanks for the bug report, and especially for the DXF file to reproduce
it. The DXF has no "entities" section, which is what caused the crash.
- Bug#895862: dxf2gcode: Crashes "Unboun... Paul "LeoNerd" Evans
- Bug#895862: dxf2gcode: Crashes "U... Sebastian Kuzminsky
