Minecraft Server - Monster gehen nicht ?

plugins=WorldGuard,LWC,Promoter,iConomy,CraftBook, MagicCarpet,CuboidPlugin,LoginMessage,BigBrother,
reservelist-txt-location=reservelist.txt
server-name=Xeon-Craft
spawn-protection-size=16
admintxtlocation=users.txt
disalloweditems=
natural-animals=Sheep,Pig,Chicken,Cow
enable-health=true
default_group=
save-homes=true
itemstxtlocation=items.txt
warplocation=warps.txt
natural-spawn-rate=2
spawn-monsters=true
admin-slot=false
max-connections=3
itemspawnblacklist=
pvp=false
grow-trees=true
data-source=flatfile
whitelist-message=Du bist nicht auf der Whitelist!
whitelist-txt-location=whitelist.txt
logging=false
verify-names=false
homelocation=homes.txt
group_ranking=
monsters=true
reservelist=false
kitstxtlocation=kits.txt
natural-monsters=
level-name=world
alloweditems=
hellworld=false
spawn-animals=false
whitelist=false
show-unknown-command=true
natural-wateranimals=Squid
online-mode=true
auto-heal=default
group-txt-location=groups.txt
motd=Herzlich Wilkommen auf PowerMine! Besuche das Forum powermine.**************\!
no-animals=false
default_group=default
group_ranking=admins,mods,vip,bau,default
public=false
server-ip=78.143.38.233
server-port=25565
max-players=18