I get this error when exiting a multiplayer game.

[Glome]

java.lang.NegativeArraySizeException
org.jbox2d.dynamics.Island.a(Island.java:118)
org.jbox2d.dynamics.PhysicsWorld.a(PhysicsWorld.java:573)
net.buildism.aa.r(World.java:742)
net.buildism.h.h(Game.java:233)
net.buildism.l.p(Main.java:776)
net.buildism.MainApplet.run(MainApplet.java:210)
java.lang.Thread.run(Unknown Source)