Im going to guess it means one of these (the exact error would help, since id be very supprised if it said "DefConAKILL missing" with AKILL all in caps like that etc... )
--
# DefConAkillExpire <time> [REQUIRED if DefCon is activated]
# Length of time to add the AKILL for when DEFCON is preventing
# all new clients from connecting to the network
#
# NOTE: As with all expire times, the expirey check will only be
# carried out once every "ExpireTimeout" so if this setting is
# 30m the the akill could last for 30m regardless of this setting.
#
# NOTE: When using DefCon this value needs to be defined
#DefConAkillExpire 5m
# DefConAkillReason <text> [REQUIRED if DefCon is activated]
#
# When using DEFCON this setting will be used when any clients are killed
# or akilled from the network by defcon
#
#DefConAkillReason "This network is currently not accepting connections, please try again later"