Hi,
It is hard to guess the cause of these problems without any additional information. Just a blind assumption - make sure you are a root user (or use sudo) when installing the pip packages.
Also - please note I am not an active user in this forum (still do not speak danish :-), so please use github for issues.
Sorry for posting in english, I do not speak danish at all :-)
I have integrated the old style IHC Controller (no ethernet, RS485 only) to Home Assistant. The code can be found at https://github.com/priiduonu/ihcclient. Comments and PR-s welcome!