Ok, you have found a bug present since 4 Dec 2011
The crash is produced by 2 empty polylines. this "bad feature" permited in old code / dxf lib are not permited in version 2, but bad checked.
Added a patch in master branch solving this issue "commit d21cb572a0"
Solution only for attached dxf:
open the dxf with a text editor and remove lines 56761 to 56800 included.
For all files:
Wait for a new ubuntu daily buid (see
http://librecad.org/cms/home/installation/linux.html)
And please, open a bug report in Debian (if you can, of course)
https://www.debian.org/Bugs/ReportingAttached the patch to solve this important bug.
emptytpline.patchCheers & thanks
Rallaz