the error message is printed at the end of the Punita001.out file.
However starting with the latest version of FLUKA (v4-4), you should not encounter these type of errors, because of the automatic use of point-wise low energy neutron cross sections.
Please update your FLUKA installation, as support is provided only for the latest release.
the error message at the end of Punita001.out file states: Low energy neutron xsec not found for some media…GRAPHITE
I will update FLUKA and I will try again.