server fails

---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 6/03/13 21:29
Description: Exception in server tick loop

java.lang.RuntimeException: Failed to check session lock, aborting
	at net.minecraft.server.v1_4_R1.WorldNBTStorage.h(WorldNBTStorage.java:55)
	at net.minecraft.server.v1_4_R1.WorldNBTStorage.<init>(WorldNBTStorage.java:40)
	at net.minecraft.server.v1_4_R1.ServerNBTManager.<init>(SourceFile:16)
	at net.minecraft.server.v1_4_R1.WorldLoaderServer.a(SourceFile:78)
	at net.minecraft.server.v1_4_R1.MinecraftServer.a(MinecraftServer.java:162)
	at net.minecraft.server.v1_4_R1.DedicatedServer.init(DedicatedServer.java:149)
	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:399)
	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
	Minecraft Version: 1.4.7
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_11, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
	Memory: 969229672 bytes (924 MB) / 1037959168 bytes (989 MB) up to 1037959168 bytes (989 MB)
	JVM Flags: 2 total; -Xms1024M -Xmx1024M
	AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: $Proxy3[com.avaje.ebean.config.dbplatform.DatabasePlatform, SQLitePlatform], [com.google.common.base.Predicate, Function, Joiner, ...], [com.google.common.collect.ImmutableCollection, ImmutableList, Maps, ...], [com.google.common.io.Files, OutputSupplier, InputSupplier], [net.minecraft.server.v1_4_R1.ICommandListener, IMojangStatistics, IDataManager, ...], [org.apache.commons.lang.Validate], [org.bukkit.World, BlockChangeDelegate, Server, ...], [org.bukkit.block.BlockState, BlockFace], [org.bukkit.command.CommandSender, RemoteConsoleCommandSender, CommandException, ...], [org.bukkit.command.defaults.VanillaCommand, SaveCommand, SaveOnCommand, ...], [org.bukkit.configuration.ConfigurationSection, Configuration, MemorySection, ...], [org.bukkit.configuration.file.FileConfiguration, YamlConfiguration, FileConfigurationOptions, ...], [org.bukkit.configuration.serialization.ConfigurationSerializable, ConfigurationSerialization, DelegateDeserialization, ...], [org.bukkit.conversations.Conversable, ConversationCanceller], [org.bukkit.craftbukkit.Main], [org.bukkit.craftbukkit.libs.com.google.gson.JsonDeserializer, JsonParseException], [org.bukkit.craftbukkit.libs.jline.TerminalFactory, Terminal, Flavor, ...], [org.bukkit.craftbukkit.libs.jline.console.ConsoleReader, CursorBuffer, ConsoleKeys, ...], [org.bukkit.craftbukkit.libs.jline.console.completer.CompletionHandler, CandidateListCompletionHandler], [org.bukkit.craftbukkit.libs.jline.console.history.History, MemoryHistory], [org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader, Configuration, Log], [org.bukkit.craftbukkit.libs.joptsimple.OptionException, OptionParser, OptionSpec, ...], [org.bukkit.craftbukkit.libs.joptsimple.internal.AbbreviationMap, ReflectionException, Reflection, ...], [org.bukkit.craftbukkit.v1_4_R1.LoggerOutputStream, CraftServer, CraftOfflinePlayer, ...], [org.bukkit.craftbukkit.v1_4_R1.command.ServerCommandSender, CraftConsoleCommandSender, ColouredConsoleSender], [org.bukkit.craftbukkit.v1_4_R1.conversations.ConversationTracker], [org.bukkit.craftbukkit.v1_4_R1.enchantments.CraftEnchantment], [org.bukkit.craftbukkit.v1_4_R1.help.SimpleHelpMap, CommandAliasHelpTopic, HelpYamlReader, ...], [org.bukkit.craftbukkit.v1_4_R1.inventory.CraftItemStack, CraftRecipe, CraftShapedRecipe, ...], [org.bukkit.craftbukkit.v1_4_R1.metadata.EntityMetadataStore, PlayerMetadataStore, WorldMetadataStore], [org.bukkit.craftbukkit.v1_4_R1.potion.CraftPotionEffectType, CraftPotionBrewer], [org.bukkit.craftbukkit.v1_4_R1.scheduler.CraftScheduler, CraftTask, CraftFuture, ...], [org.bukkit.craftbukkit.v1_4_R1.updater.AutoUpdater, BukkitDLUpdaterService, DateDeserializer], [org.bukkit.craftbukkit.v1_4_R1.util.Waitable, ServerShutdownThread, TerminalConsoleHandler, ...], [org.bukkit.enchantments.Enchantment, EnchantmentWrapper], [org.bukkit.entity.Entity, Damageable, LivingEntity, ...], [org.bukkit.event.Event, Cancellable], [org.bukkit.event.block.BlockEvent, BlockFadeEvent, BlockGrowEvent, ...], [org.bukkit.event.entity.EntityEvent, EntityInteractEvent, EntityDamageEvent, ...], [org.bukkit.event.hanging.HangingEvent, HangingPlaceEvent], [org.bukkit.event.painting.PaintingEvent, PaintingPlaceEvent], [org.bukkit.event.player.PlayerEvent, PlayerInteractEvent, PlayerFishEvent, ...], [org.bukkit.event.server.ServerEvent, MapInitializeEvent, ServerCommandEvent, ...], [org.bukkit.event.world.WorldEvent, WorldSaveEvent, WorldInitEvent, ...], [org.bukkit.help.HelpMap, HelpTopic, IndexHelpTopic, ...], [org.bukkit.inventory.ItemStack, Recipe, ShapedRecipe, ...], [org.bukkit.inventory.meta.ItemMeta, Repairable, BookMeta, ...], [org.bukkit.map.MapView], [org.bukkit.material.MaterialData, Tree, Directional, ...], [org.bukkit.metadata.Metadatable, MetadataStore, MetadataStoreBase], [org.bukkit.permissions.ServerOperator, Permissible, PermissibleBase], [org.bukkit.plugin.ServicesManager, PluginManager, SimpleServicesManager, ...], [org.bukkit.plugin.java.JavaPluginLoader, PluginClassLoader], [org.bukkit.plugin.messaging.PluginMessageRecipient, Messenger, StandardMessenger, ...], [org.bukkit.potion.PotionEffectType, PotionEffectTypeWrapper, PotionBrewer, ...], [org.bukkit.scheduler.BukkitScheduler, BukkitTask], [org.bukkit.util.Vector, BlockVector, Java15Compat, ...], [org.fusesource.hawtjni.runtime.Library], [org.fusesource.jansi.AnsiOutputStream, WindowsAnsiOutputStream, AnsiConsole, ...], [org.fusesource.jansi.internal.Kernel32, CONSOLE_SCREEN_BUFFER_INFO, COORD, ...], [org.yaml.snakeyaml.DumperOptions, ScalarStyle, FlowStyle, ...], [org.yaml.snakeyaml.composer.Composer, ComposerException], [org.yaml.snakeyaml.constructor.BaseConstructor, SafeConstructor, Constructor, ...], [org.yaml.snakeyaml.emitter.Emitable, Emitter, EmitterException, ...], [org.yaml.snakeyaml.error.YAMLException, MarkedYAMLException, Mark], [org.yaml.snakeyaml.events.Event, NodeEvent, AliasEvent, ...], [org.yaml.snakeyaml.external.com.google.gdata.util.common.base.Escaper, UnicodeEscaper, PercentEscaper], [org.yaml.snakeyaml.introspector.PropertyUtils, BeanAccess], [org.yaml.snakeyaml.nodes.Node, CollectionNode, MappingNode, ...], [org.yaml.snakeyaml.parser.Parser, ParserImpl, ParserException, ...], [org.yaml.snakeyaml.reader.UnicodeReader, StreamReader, ReaderException], [org.yaml.snakeyaml.representer.BaseRepresenter, SafeRepresenter, Representer, ...], [org.yaml.snakeyaml.resolver.Resolver, ResolverTuple], [org.yaml.snakeyaml.scanner.Scanner, ScannerImpl, ScannerException, ...], [org.yaml.snakeyaml.serializer.Serializer, SerializerException], [org.yaml.snakeyaml.tokens.Token, AliasToken, ScalarToken, ...], [org.yaml.snakeyaml.util.UriEncoder, ArrayStack]
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	CraftBukkit Information: 
   Running: CraftBukkit version git-Bukkit-1.4.7-R1.0-b2624jnks (MC: 1.4.7) (Implementing API version 1.4.7-R1.0) false
   Plugins: {}
   Warnings: DEFAULT
   Threads: { RUNNABLE Thread-6: [java.net.SocketInputStream.socketRead0(Native Method), java.net.SocketInputStream.read(Unknown Source), java.net.SocketInputStream.read(Unknown Source), java.io.BufferedInputStream.fill(Unknown Source), java.io.BufferedInputStream.read1(Unknown Source), java.io.BufferedInputStream.read(Unknown Source), sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source), sun.net.www.http.HttpClient.parseHTTP(Unknown Source), sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source), org.bukkit.craftbukkit.v1_4_R1.updater.BukkitDLUpdaterService.fetchArtifact(BukkitDLUpdaterService.java:49), org.bukkit.craftbukkit.v1_4_R1.updater.BukkitDLUpdaterService.getArtifact(BukkitDLUpdaterService.java:28), org.bukkit.craftbukkit.v1_4_R1.updater.AutoUpdater$1.run(AutoUpdater.java:77)], WAITING Snooper Timer: [java.lang.Object.wait(Native Method), java.lang.Object.wait(Object.java:503), java.util.TimerThread.mainLoop(Unknown Source), java.util.TimerThread.run(Unknown Source)], RUNNABLE Listen thread: [java.net.DualStackPlainSocketImpl.accept0(Native Method), java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source), java.net.AbstractPlainSocketImpl.accept(Unknown Source), java.net.PlainSocketImpl.accept(Unknown Source), java.net.ServerSocket.implAccept(Unknown Source), java.net.ServerSocket.accept(Unknown Source), net.minecraft.server.v1_4_R1.DedicatedServerConnectionThread.run(DedicatedServerConnectionThread.java:62)], RUNNABLE Signal Dispatcher: [], RUNNABLE Attach Listener: [], TIMED_WAITING Thread-4: [java.lang.Thread.sleep(Native Method), net.minecraft.server.v1_4_R1.ThreadSleepForever.run(SourceFile:52)], RUNNABLE Server thread: [java.lang.Thread.dumpThreads(Native Method), java.lang.Thread.getAllStackTraces(Unknown Source), org.bukkit.craftbukkit.v1_4_R1.CraftCrashReport.call(CraftCrashReport.java:28), net.minecraft.server.v1_4_R1.CrashReportSystemDetails.a(SourceFile:74), net.minecraft.server.v1_4_R1.CrashReport.h(CrashReport.java:43), net.minecraft.server.v1_4_R1.CrashReport.<init>(CrashReport.java:30), net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:444), net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)], WAITING Reference Handler: [java.lang.Object.wait(Native Method), java.lang.Object.wait(Object.java:503), java.lang.ref.Reference$ReferenceHandler.run(Unknown Source)], RUNNABLE DestroyJavaVM: [], RUNNABLE Thread-5: [org.fusesource.jansi.internal.Kernel32._getch(Native Method), org.fusesource.jansi.internal.WindowsSupport.readByte(WindowsSupport.java:46), org.bukkit.craftbukkit.libs.jline.WindowsTerminal.readByte(WindowsTerminal.java:184), org.bukkit.craftbukkit.libs.jline.WindowsTerminal.access$000(WindowsTerminal.java:53), org.bukkit.craftbukkit.libs.jline.WindowsTerminal$1.read(WindowsTerminal.java:151), java.io.FilterInputStream.read(Unknown Source), org.bukkit.craftbukkit.libs.jline.console.ConsoleReader$1.read(ConsoleReader.java:167), org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:267), org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:204), org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readCharacter(ConsoleReader.java:995), org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readLine(ConsoleReader.java:1167), net.minecraft.server.v1_4_R1.ThreadCommandReader.run(ThreadCommandReader.java:31)], WAITING Finalizer: [java.lang.Object.wait(Native Method), java.lang.ref.ReferenceQueue.remove(Unknown Source), java.lang.ref.ReferenceQueue.remove(Unknown Source), java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source)],}
   Recent tasks from -31--1{}
	Profiler Position: N/A (disabled)
	Player Count: 0 / 5; []
	Is Modded: Definitely; Server brand changed to 'craftbukkit'
	Type: Dedicated Server (map_server.txt)