i tryed changing the version of the ftb unleashed modpack but that didin't work anyways here is the log
if you need more info just pm me or reply
---- Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!
Time: 10/17/13 7:23 PM
Description: Exception in server tick loop
java.lang.RuntimeException: java.io.FileNotFoundException: .\world\chickenchunks\loginTimes.dat (The requested operation cannot be performed on a file with a user-mapped section open)
at codechicken.chunkloader.ChunkLoaderManager.updateLoginTimes(ChunkLoaderManager.java:872)
at codechicken.chunkloader.ChunkLoaderManager.tickEnd(ChunkLoaderManager.java:840)
at codechicken.chunkloader.ChunkLoaderEventHandler.tickEnd(ChunkLoaderEventHandler.java:39)
at cpw.mods.fml.common.SingleIntervalHandler.tickEnd(SingleIntervalHandler.java:34)
at cpw.mods.fml.common.FMLCommonHandler.tickEnd(FMLCommonHandler.java:141)
at cpw.mods.fml.common.FMLCommonHandler.onPostWorldTick(FMLCommonHandler.java:282)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:663)
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:275)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:573)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:470)
at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573)
Caused by: java.io.FileNotFoundException: .\world\chickenchunks\loginTimes.dat (The requested operation cannot be performed on a file with a user-mapped section open)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.FileOutputStream.<init>(Unknown Source)
at codechicken.chunkloader.ChunkLoaderManager.updateLoginTimes(ChunkLoaderManager.java:861)
... 10 more
if you need more info just pm me or reply