Welcome to the forum!
This may well be a problem for which we need developer input. And unfortunately, devs rarely participate in forums. We have some members who have developer-like knowledge, up to a point. So we can try to sort it out here. But in the end, you may need to communicate directly with devs. You can do that via the User or Development mailing lists, User or Development IRC, or by filing a bug report in the bug tracker. IRC and mailing list info here:
https://inkscape.org/en/community/ Bug tracker:
https://launchpad.net/inkscape If you decide to go straight for the bug tracker, be sure to search first, before posting the bug, in case it's already been reported.
When I try to open the DXF file in Inkscape, I also get a Traceback error. But mine has a little more info:
Traceback (most recent call last):
File "dxf_input.py", line 530, in <module>
inkex.errormsg(_('%d ENTITIES of type POLYLINE encountered and ignored. Please try to convert to Release 13 format using QCad.') % polylines)
NameError: name '_' is not defined
Beyond that, I can't help. I can't even decipher what the error means. But others will be along before too long