Description: Unexpected error

java.lang.IndexOutOfBoundsException: Index: 6, Size: 0
        at java.util.ArrayList.rangeCheck(Unknown Source)
        at java.util.ArrayList.get(Unknown Source)
        at net.minecraft.inventory.Container.func_75139_a(SourceFile:104)
        at net.minecraft.inventory.Container.func_75141_a(SourceFile:385)
        at net.minecraft.client.network.NetHandlerPlayClient.func_147266_a(NetHandlerPlayClient.java:1029)
        at net.minecraft.network.play.server.S2FPacketSetSlot.func_148833_a(SourceFile:27)
        at net.minecraft.network.play.server.S2FPacketSetSlot.func_148833_a(SourceFile:10)
        at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:212)
        at net.minecraft.client.multiplayer.PlayerControllerMP.func_78765_e(PlayerControllerMP.java:273)
        at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1601)
        at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:972)
        at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898)
        at net.minecraft.client.main.Main.main(SourceFile:148)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)