As I am very experienced in running Tekkit Server this error stumped me. It only seems to happen when someone logs in. We found the person, there is nothing wrong with him. The next server restart, he is able to login fine.
If someone could he me locate the chunk or what is causing this that would be great.
2013-12-01 16:20:49 [sEVERE] java.util.ConcurrentModificationException
2013-12-01 16:20:49 [sEVERE]at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
2013-12-01 16:20:49 [sEVERE]at java.util.ArrayList$Itr.next(Unknown Source)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.World.getTileEntity(World.java:1644)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.WorldServer.getTileEntity(WorldServer.java:45)
2013-12-01 16:20:49 [sEVERE]at ee.TileCollector3.sendEnergy(TileCollector3.java:478)
2013-12-01 16:20:49 [sEVERE]at ee.TileCollector3.sendAllPackets(TileCollector3.java:494)
2013-12-01 16:20:49 [sEVERE]at ee.TileCollector3.q_(TileCollector3.java:631)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.World.tickEntities(World.java:1190)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:467)
2013-12-01 16:20:49 [sEVERE]at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
2013-12-01 16:20:49 [sEVERE] Unexpected exception
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
at java.util.ArrayList$Itr.next(Unknown Source)
at net.minecraft.server.World.getTileEntity(World.java:1644)
at net.minecraft.server.WorldServer.getTileEntity(WorldServer.java:45)
at ee.TileCollector3.sendEnergy(TileCollector3.java:478)
at ee.TileCollector3.sendAllPackets(TileCollector3.java:494)
at ee.TileCollector3.q_(TileCollector3.java:631)
at net.minecraft.server.World.tickEntities(World.java:1190)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:467)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Any help would be appreciated.