Please follow the submission template and guidelines and make a complete, valid bug report, with required info, precise description of the issue, precise steps to reproduce it, small and simple .blend and/or other files to do so if needed, etc.
A guideline for making a good bug report can be found here: https://wiki.blender.org/wiki/Process/Bug_Reports
Watch this video on How to Report a Bug
Furthermore, note that you're reporting about the wrong add-on because the error messages refer to Archipack and not Archimesh.
We also no longer handle bug reports for 2.79.
If you can reproduce this bug in 2.80 or newer, make a new report to the add-on tracker: