Remember to use WikiFormatting, to fill in the Port field, to Cc the maintainer of that port, and to use a descriptive Summary.
The relevant error in the log seems to be:
:info:destroot Can't locate RRDs.pm in @INC (@INC contains: ./libexec ./installer-items /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_net_nfsen/nfsen/work/destroot/opt/local/libexec/nfsen /opt/local/libexec/nfsen /opt/local/lib/perl5/site_perl/5.12.4/darwin-thread-multi-2level /opt/local/lib/perl5/site_perl/5.12.4 /opt/local/lib/perl5/vendor_perl/5.12.4/darwin-thread-multi-2level /opt/local/lib/perl5/vendor_perl/5.12.4 /opt/local/lib/perl5/5.12.4/darwin-thread-multi-2level /opt/local/lib/perl5/5.12.4 /opt/local/lib/perl5/site_perl /opt/local/lib/perl5/vendor_perl .) at libexec/NfSenRRD.pm line 38.
This sounds similar to #22922.
We need to update nfsen to a newer version. See #22923. I have tried a few times over the months and years to do so but it is difficult to get it working.
