2013-07-04 22:07:44 [WARNING] Failed to handle packet for XxWolf5252Xx/71.223.128.125: net.minecraft.server.v1_6_R1.ReportedException: Ticking player
net.minecraft.server.v1_6_R1.ReportedException: Ticking player
	at net.minecraft.server.v1_6_R1.EntityPlayer.h(EntityPlayer.java:270)
	at net.minecraft.server.v1_6_R1.PlayerConnection.a(PlayerConnection.java:364)
	at net.minecraft.server.v1_6_R1.Packet10Flying.handle(SourceFile:136)
	at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:237)
	at net.minecraft.server.v1_6_R1.PlayerConnection.d(PlayerConnection.java:118)
	at net.minecraft.server.v1_6_R1.ServerConnection.b(SourceFile:37)
	at org.spigotmc.netty.NettyServerConnection.b(NettyServerConnection.java:125)
	at net.minecraft.server.v1_6_R1.MinecraftServer.t(MinecraftServer.java:592)
	at net.minecraft.server.v1_6_R1.DedicatedServer.t(DedicatedServer.java:235)
	at net.minecraft.server.v1_6_R1.MinecraftServer.s(MinecraftServer.java:481)
	at net.minecraft.server.v1_6_R1.MinecraftServer.run(MinecraftServer.java:413)
	at net.minecraft.server.v1_6_R1.ThreadServerApplication.run(SourceFile:582)
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Byte
	at net.minecraft.server.v1_6_R1.DataWatcher.getByte(SourceFile:79)
	at net.minecraft.server.v1_6_R1.EntityLiving.aF(EntityLiving.java:452)
	at net.minecraft.server.v1_6_R1.EntityLiving.x(EntityLiving.java:229)
	at net.minecraft.server.v1_6_R1.Entity.l_(Entity.java:240)
	at net.minecraft.server.v1_6_R1.EntityLiving.l_(EntityLiving.java:1226)
	at net.minecraft.server.v1_6_R1.EntityHuman.l_(EntityHuman.java:157)
	at net.minecraft.server.v1_6_R1.EntityPlayer.h(EntityPlayer.java:222)

ALSO, This Error:

2013-07-04 22:04:14 [WARNING] A task raised an exception.
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Byte
	at net.minecraft.server.v1_6_R1.DataWatcher.a(SourceFile:212)
	at net.minecraft.server.v1_6_R1.DataWatcher.a(SourceFile:148)
	at net.minecraft.server.v1_6_R1.Packet40EntityMetadata.a(SourceFile:36)
	at org.spigotmc.netty.PacketWriter.write(PacketWriter.java:66)
	at org.spigotmc.netty.NettyNetworkManager.queue0(NettyNetworkManager.java:203)
	at org.spigotmc.netty.NettyNetworkManager.access$000(NettyNetworkManager.java:34)
	at org.spigotmc.netty.NettyNetworkManager$3.run(NettyNetworkManager.java:182)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:353)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:365)
	at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:101)
	at java.lang.Thread.run(Unknown Source)