Server Tick Loop Crash

Crash.log

19:55:59 [SEVERE] net.minecraft.server.ReportedException: Ticking entity
19:56:00 [SEVERE]       at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:573)
19:56:00 [SEVERE]       at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:223)
19:56:00 [SEVERE]       at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:482)
19:56:00 [SEVERE]       at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:417)
19:56:00 [SEVERE]       at net.minecraft.server.ThreadServerApplication.run(SourceFile:849)
19:56:00 [SEVERE] Caused by: java.lang.NoSuchMethodError: net.minecraft.server.EntityCreeper.aG()Lnet/minecraft/server/EntityLiving;
19:56:00 [SEVERE]       at net.minecraft.server.PathfinderGoalSwell.a(SourceFile:18)
19:56:00 [SEVERE]       at net.minecraft.server.PathfinderGoalSelector.a(PathfinderGoalSelector.java:66)
19:56:00 [SEVERE]       at net.minecraft.server.EntityLiving.bl(EntityLiving.java:1480)
19:56:00 [SEVERE]       at net.minecraft.server.EntityLiving.c(EntityLiving.java:1273)
19:56:00 [SEVERE]       at net.minecraft.server.EntityMonster.c(EntityMonster.java:20)
19:56:00 [SEVERE]       at net.minecraft.server.EntityLiving.j_(EntityLiving.java:534)
19:56:00 [SEVERE]       at net.minecraft.server.EntityMonster.j_(EntityMonster.java:24)
19:56:00 [SEVERE]       at net.minecraft.server.EntityCreeper.j_(EntityCreeper.java:112)
19:56:00 [SEVERE]       at net.minecraft.server.World.tickEntity(World.java:1487)
19:56:00 [SEVERE]       at net.minecraft.server.World.entityJoinedWorld(World.java:1448)
19:56:00 [SEVERE]       at net.minecraft.server.WorldServer.entityJoinedWorld(WorldServer.java:579)
19:56:00 [SEVERE]       at net.minecraft.server.World.playerJoinedWorld(World.java:1438)
19:56:00 [SEVERE]       at net.minecraft.server.World.tickEntities(World.java:1316)
19:56:00 [SEVERE]       at net.minecraft.server.WorldServer.tickEntities(WorldServer.java:470)
19:56:00 [SEVERE]       at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:569)
19:56:00 [SEVERE]       ... 4 more
19:56:00 [SEVERE] Encountered an unexpected exception ReportedException
net.minecraft.server.ReportedException: Ticking entity
        at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:573)
        at net.minecraft.server.DedicatedServer.r(DedicatedServer.java:223)
        at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:482)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:417)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NoSuchMethodError: net.minecraft.server.EntityCreeper.aG()Lnet/minecraft/server/EntityLiving;
        at net.minecraft.server.PathfinderGoalSwell.a(SourceFile:18)
        at net.minecraft.server.PathfinderGoalSelector.a(PathfinderGoalSelector.java:66)
        at net.minecraft.server.EntityLiving.bl(EntityLiving.java:1480)
        at net.minecraft.server.EntityLiving.c(EntityLiving.java:1273)
        at net.minecraft.server.EntityMonster.c(EntityMonster.java:20)
        at net.minecraft.server.EntityLiving.j_(EntityLiving.java:534)
        at net.minecraft.server.EntityMonster.j_(EntityMonster.java:24)
        at net.minecraft.server.EntityCreeper.j_(EntityCreeper.java:112)
        at net.minecraft.server.World.tickEntity(World.java:1487)
        at net.minecraft.server.World.entityJoinedWorld(World.java:1448)
        at net.minecraft.server.WorldServer.entityJoinedWorld(WorldServer.java:579)
        at net.minecraft.server.World.playerJoinedWorld(World.java:1438)
        at net.minecraft.server.World.tickEntities(World.java:1316)
        at net.minecraft.server.WorldServer.tickEntities(WorldServer.java:470)
        at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:569)
        ... 4 more
19:56:00 [SEVERE] This crash report has been saved to: /home/dotcloud/data/mcserver/./crash-reports/crash-2013-01-20_19.56.00-server.txt