Portals will not work!

I was playing some survival with a few friends on my server which is being created. We had just created a nether portal, when we find out it wont work! When we try and stand inside the portal, nothing happens, the screen just stays swirly. The same happens with the End Portal. Any suggestions?

Plugin List:
AutoMessage
BattleArena
Buycraft
ChatManager
ClearLag
CookieMonster
CoreProtect
DisguiseCraft
Essentials Pre2.11.1.6
EssentialsAntiBuild
EssentialsChat
EssentialsProtect
EssentialsSpawn
Faction
FoundDiamonds
GeoIPTools
MCBans
BukkitCompat
McMyAdmin
MobArena
Multiverse-Core
Multiverse-Portoals
NoCheatPlus
OnTime
Parkour
PermissionsEx .
ProtocolLib
SignShop
SuperSpleef
Vault
WorldBorder
WorldEdit
WorldGuard
WorldGuardFlagger
iConomy
mcMMO