PlayerPortalEvent to Multiverse-Core error

Hallo,

My server crashed sometimes when i go to the portals, i read something about that you get the error by set the portal in the place you protect with worldedit. But i don't know how to fix that. Can somebody please help me.

thank you.

My plugins are:
byeHunger
Citizens
Clearlag
DisableMessage
DoubleJump
Essentials
EssentialsChat
EssentialsGroupManager
EssentialsSpawn
FirstjoinPlus
GriefProvention
HolographicDisplays
Kingkits
LagMeter
Multiverse-Core 2.5
Multiverse-Inventories 2.5
Multiverse-Portals
Multiworld
NoFallDamage
Plotsquared
PowerMOTD
SeePlayerInventory
Signs
SimpleAutoMessage
SimpleBackup
Titlebar
Vault
WelcomeTitle
Worldedit
WorldGaurd