Many thanks for the feedback.
I'm not be able to reproduce this issue. I think this comes due of the new perl package (
https://www.archlinux.org/news/perl-library-path-change/). The ISO is a little out of date, i will provide a next one on this week.
Simply, update first the entire system :
# sudo pacman -Syyu
Then try to install again, do not forget to answer y when the script ask you to update obarun-install and obarun-install-themes
It should work, if it's not the case, please tell me it