It seems clear that you have a broken/incomplete installation. How severe an issue this is depends on where/how the installation encountered the error. This is basically impossible to diagnose without the detailed support file from the system in question (as described in the user guide, second-to-last page).
The procedure for getting support for ArcaOS installation (and other) problems is to start by opening a problem ticket with Arca Noae (see Appendix G of the guide). Unless you do that, we really can't help you.
FWIW, the most important installation logfile is LCU.L2 (not an especially intuitive name, I know). This shows the overall status of the install process, and will generally allow you to see where the installation was interrupted. However, for full diagnosis, all the logs AND response files will be required for analysis. The support file (see above) will contain this.