Before using multimon and the other CGI programs, first ensure that
apcupsd is configured to run the Network Information Server. This is
done by setting NETSERVER on in ${SYSCONFDIR}/apcupsd/apcupsd.conf. 
This switch is on by default.
To run scripts in chrooted apache (default behaviour), configuration
files must be available to the webserver:
# mv ${SYSCONFDIR}/apcupsd /var/www/${SYSCONFDIR}/apcupsd
# ln -s /var/www/${SYSCONFIDR}/apcupsd ${SYSCONFDIR}/
And some libraries must be copied in:
# ${WEB_ROOT}/cgi-bin/apcupsd/copy-libs.sh