tekkit classic server crashing within 10-15 seconds of logging on

[ahwtx]

i'm running tekkit classic 3.1.3 and i have both the server and the client running on the same machine simultaneously.

my system specs are as follows:

cpu: xeon x3440 (2.53ghz quad-core, hyperthreaded)

ram: 12gb ddr3 1600

gpu: radeon hd 6870

ssd: 128gb crucial m4 (both the client and server are installed here)

os: win7 pro x64 sp1

i fire up the server. i fire up the client. i connect to the server. within 10-15 seconds i get disconnected and the server log reads as follows:

2013-02-15 17:27:07 [iNFO] ahwtx [/127.0.0.1:49387] logged in with entity id 377 at ([lukejas] 104.46261590823559, 76.0, 266.84705199123226)

2013-02-15 17:27:07 [iNFO] ahwtx joined with: [CodeChickenCore 0.5.3, MinecraftForge 3.3.8.164, NotEnoughItems 1.2.2.4, ReiMinimap v3.2_04 [1.2.5], IC2 v1.103, IC2AdvancedMachines v4.0, BuildCraftCore 2.2.14, BuildCraftBuilders 2.2.14, BuildCraftEnergy 2.2.14, BuildCraftFactory 2.2.14, BuildCraftTransport 2.2.14, AdditionalPipes 2.1.3 (Minecraft 1.2.5, Buildcraft 2.2.14, Forge 3.0.1.75), ComputerCraft 1.41, RedPowerMachine 2.0pr5b2, ccSensors MC1.2.5 Build017pr1, CCTurtle 1.41, EE 1.4.6.5, EnderStorage 1.1.3, IC2NuclearControl v1.1.10, ImmibisCore 49.1.1, InvTweaks 1.41b (1.2.4), MAtmos_forModLoader r12 for 1.1.x, ModularForceFieldSystem rev7, IC2_ChargingBench 1.95b, CompactSolars 2.3.2, IronChest 3.8, RedPowerCore 2.0pr5b2, NetherOres 1.2.5R1.2.2, PowerConverters 1.2.5R1.3.4, Railcraft 5.4.7, RedPowerControl 2.0pr5b2, RedPowerLighting 2.0pr5b2, RedPowerLogic 2.0pr5b2, RedPowerWiring 2.0pr5b2, RedPowerWorld 2.0pr5b2, TubeStuff 49.1.2, Balkon's WeaponMod 1.2.5 v8.6.0, WirelessRedstoneCore 1.2.2.3, WirelessRedstoneAddons 1.2.2.3, WirelessRedstoneRedPower 1.2.2.1, ImmiChunkLoaders rev3.2]

2013-02-15 17:27:07 [iNFO] Sending serverside check to: ahwtx

2013-02-15 17:27:43 [WARNING] Failed to handle packet: java.lang.ArrayIndexOutOfBoundsException

java.lang.ArrayIndexOutOfBoundsException

    at net.minecraft.server.Packet51MapChunk.<init>(Packet51MapChunk.java:89)

    at net.minecraft.server.EntityPlayer.a(EntityPlayer.java:271)

    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:334)

    at net.minecraft.server.Packet10Flying.handle(SourceFile:126)

    at net.minecraft.server.NetworkManager.b(NetworkManager.java:251)

    at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:106)

    at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:82)

    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)

    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:457)

    at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

what gives here?! i have absolutely no idea how to even begin to troubleshoot this issue.

the only additional plugin i've installed beyond what's included by default is safe creeper. everything was just fine yesterday. i played for nearly 5 hours straight without a hiccup. now today i'm getting this. i've had the errant crash here and there (both client and server) but i've just chalked this up to the joy that is minecraft. did one of those errant crashes utterly bork/corrupt my world somehow?

edit with an update:

i ran region fixer on my world files and found no corrupted or out of place chunks. i also completely deleted all of the server files and downloaded and ran a fresh copy of the server to no avail. (i carried over my backed up world files from the original server install.)

is it really worth the hassle of uninstalling and reinstalling java entirely at this point as well? i forgot to mention initially that i am running 64 bit java, version 7 update 10.

one last edit with one last update:

after generating a fresh world with a fresh seed, i'm getting no crashes. so apparently my world is corrupt somehow, but i have absolutely no idea how. PLEASE tell me there's a way to fix this? my friend and i were so far along in that world... if i lose it, well i'm going to actually "lose it" (as in my mind) i think. :/