shopkeeper crash


2013-05-11 18:45:57 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-05-11 18:45:57 [INFO] [[0;31;1mNether[0;37;1m][0;37;22m[[0;30;1mNC[0;37;22m][0;32;1m[[0;35;22mMod[0;32;1m][0;35;22m~[0;35;22mOatTheHappyEnderman[0;37;1m: nope[m
2013-05-11 18:45:58 [WARNING] [Shopkeepers] Task #18024130 for Shopkeepers v1.13.2 generated an exception
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.remove(Unknown Source)
	at com.nisovin.shopkeepers.ShopkeepersPlugin$4.run(ShopkeepersPlugin.java:583)
	at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftTask.run(CraftTask.java:53)
	at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
	at net.minecraft.server.v1_5_R3.MinecraftServer.r(MinecraftServer.java:513)
	at net.minecraft.server.v1_5_R3.DedicatedServer.r(DedicatedServer.java:226)
	at net.minecraft.server.v1_5_R3.MinecraftServer.q(MinecraftServer.java:477)
	at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:410)
	at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
2013-05-11 18:45:59 [INFO] [0;33;22m[0;33;22m[AntiLag] [0;31;1mWarning Ground items will be removed in one minute![m
2013-05-11 18:45:59 [INFO] [Buycraft] Package checker successfully executed.
2013-05-11 18:46:00 [INFO] [TownyChat] onPlayerChat: Processing directed message for staff
2013-05-11 18:46:00 [INFO] [[0;32;1mSurvival[0;37;1m][0;35;22m[SC][0;32;1m[[0;35;22mMod[0;32;1m][0;35;22m~[0;35;22mHerz[0;37;1m: no any rank can join[m
2013-05-11 18:46:00 [INFO] firestingray¬ße was shot by Skeleton¬ße.
2013-05-11 18:46:00 [INFO] DawnMurder issued server command: /spleef join
2013-05-11 18:46:00 [INFO] [0;33;22mThere are [0;31;1m17[0;33;22m out of maximum [0;31;1m50[0;33;22m players online.[m
2013-05-11 18:46:00 [INFO] [[0;31;1mNether[0;37;1m][0;37;22m[[0;30;1mNC[0;37;22m][0;32;1m[[0;35;22mMod[0;32;1m][0;35;22m~[0;35;22mOatTheHappyEnderman[0;37;1m: not that ik of[m
2013-05-11 18:46:00 [INFO] Players[m:AwesomeAndy17[0;37;1m, Blkshroud[0;37;1m, D73r3k[0;37;1m, DawnMurder[0;37;1m, firestingray[0;37;1m, flames49003[0;37;1m, IronHawx[0;37;1m, jimmy1970[0;37;1m, Rasputin101[0;37;1m, TomParki[0;37;1m, ~[0;35;22mAzure[0;37;1m, ~[0;35;22mHerz[0;37;1m, ~[0;33;22mInsane_WJS[0;37;1m, ~Itear[0;37;1m, ~[0;35;22mJencat[0;37;1m, ~Lego[0;37;1m, ~[0;35;22mOatTheHappyEnderman[0;37;1m[m
2013-05-11 18:46:01 [WARNING] [Shopkeepers] Task #18024286 for Shopkeepers v1.13.2 generated an exception
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.remove(Unknown Source)
	at com.nisovin.shopkeepers.ShopkeepersPlugin$4.run(ShopkeepersPlugin.java:583)
	at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftTask.run(CraftTask.java:53)
	at org.bukkit.craftbukkit.v1_5_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
	at net.minecraft.server.v1_5_R3.MinecraftServer.r(MinecraftServer.java:513)
	at net.minecraft.server.v1_5_R3.DedicatedServer.r(DedicatedServer.java:226)
	at net.minecraft.server.v1_5_R3.MinecraftServer.q(MinecraftServer.java:477)
	at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:410)
	at net.minecraft.server.v1_5_R3.ThreadServerApplication.run(SourceFile:573)
2013-05-11 18:46:02 [INFO] [ModReq] The current and the lastest version do not match, a newer version must be available! (or you are running an Alfa/Beta build)
2013-05-11 18:46:04 [INFO] itearpusssy issued server command: /spleef vote nether