Warning: WorldLock failed to save worldlock.dat!
java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
        at java.util.HashMap$KeyIterator.next(Unknown Source)
        at com.bukkit.obliviousonion.WorldLock.WorldLock.saveLock(WorldLock.java
:105)
        at com.bukkit.obliviousonion.WorldLock.WorldLock.access$0(WorldLock.java
:80)
        at com.bukkit.obliviousonion.WorldLock.WorldLock$1.actionPerformed(World
Lock.java:47)
        at javax.swing.Timer.fireActionPerformed(Unknown Source)
        at javax.swing.Timer$DoPostEvent.run(Unknown Source)
        at java.awt.event.InvocationEvent.dispatch(Unknown Source)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)