Error while testing a private mod pack! Related to Railcraft

---- Minecraft Crash Report ----
// I feel sad now

Time: 10/17/13 2:21 PM
Description: Ticking tile entity

java.lang.IllegalAccessError: tried to access method net.minecraft.server.management.PlayerManager.func_72690_a(IIZ)Lnet/minecraft/server/management/PlayerInstance; from class mods.railcraft.common.util.network.PacketBuilder
at mods.railcraft.common.util.network.PacketBuilder.sendTileEntityPacket(PacketBuilder.java:39)
at mods.railcraft.common.blocks.RailcraftTileEntity.func_70316_g(RailcraftTileEntity.java:33)
at mods.railcraft.common.blocks.hidden.TileHidden.func_70316_g(TileHidden.java:34)
at net.minecraft.world.World.func_72939_s(World.java:2209)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:550)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:668)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:587)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:175)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:484)
at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:583)


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

-- Head --
Stacktrace:
at mods.railcraft.common.util.network.PacketBuilder.sendTileEntityPacket(PacketBuilder.java:39)
at mods.railcraft.common.blocks.RailcraftTileEntity.func_70316_g(RailcraftTileEntity.java:33)
at mods.railcraft.common.blocks.hidden.TileHidden.func_70316_g(TileHidden.java:34)

-- Tile entity being ticked --
Details:
Name: RCHiddenTile // mods.railcraft.common.blocks.hidden.TileHidden
Block type: ID #473 (tile.railcraft.hidden // mods.railcraft.common.blocks.hidden.BlockHidden)
Block data value: 0 / 0x0 / 0b0000
Block location: World: (-845,56,807), Chunk: (at 3,3,7 in -53,50; contains blocks -848,0,800 to -833,255,815), Region: (-2,1; contains chunks -64,32 to -33,63, blocks -1024,0,512 to -513,255,1023)
Actual block type: ID #473 (tile.railcraft.hidden // mods.railcraft.common.blocks.hidden.BlockHidden)
Actual block data value: 0 / 0x0 / 0b0000
Stacktrace:
at net.minecraft.world.World.func_72939_s(World.java:2209)
at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:550)

-- Affected level --
Details:
Level name: Test World
All players: 1 total; [EntityPlayerMP['TheMapMakerX'/73, l='Test World', x=-844.50, y=56.00, z=807.50]]
Chunk stats: ServerChunkCache: 1283 Drop: 0
Level seed: -1023262625812298900
Level generator: ID 01 - flat, ver 0. Features enabled: true
Level generator options: 2;7,3x1,52x24;2;
Level spawn location: World: (-840,4,808), Chunk: (at 8,0,8 in -53,50; contains blocks -848,0,800 to -833,255,815), Region: (-2,1; contains chunks -64,32 to -33,63, blocks -1024,0,512 to -513,255,1023)
Level time: 360 game time, 360 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 77355 (now: false), thunder time: 177674 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:668)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:587)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:175)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:484)
at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:583)

-- System Details --
Details:
Minecraft Version: 1.6.4
Operating System: Windows XP (x86) version 5.1
Java Version: 1.7.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 41490584 bytes (39 MB) / 518979584 bytes (494 MB) up to 518979584 bytes (494 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
AABB Pool Size: 285 (15960 bytes; 0 MB) allocated, 61 (3416 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v8.11 FML v6.4.30.933 Minecraft Forge 9.11.1.933 Optifine OptiFine_1.6.4_HD_U_C5 37 mods loaded, 37 mods active
mcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
FML{6.4.30.933} [Forge Mod Loader] (minecraftforge-9.11.1.933.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Forge{9.11.1.933} [Minecraft Forge] (minecraftforge-9.11.1.933.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
CodeChickenCore{0.9.0.6} [CodeChicken Core] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
NotEnoughItems{1.6.1.5} [Not Enough Items] (NotEnoughItems 1.6.1.5.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
PowerCrystalsCore{1.1.8} [PowerCrystals Core] (PowerCrystalsCore-1.1.8-7.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Backpack{1.18.17} [Backpack] (backpack-1.18.17-1.6.2.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Core{4.1.0} [BuildCraft] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Builders{4.1.0} [BC Builders] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Energy{4.1.0} [BC Energy] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Factory{4.1.0} [BC Factory] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Transport{4.1.0} [BC Transport] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
BuildCraft|Silicon{4.1.0} [BC Silicon] (buildcraft-A-1.6.2-4.1.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
EnderStorage{1.4.3.4} [EnderStorage] (EnderStorage 1.4.3.4.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
IC2{2.0.271-experimental} [IndustrialCraft 2] (industrialcraft-2_2.0.271-experimental.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Railcraft{8.1.0.0} [Railcraft] (Railcraft_1.6.2-8.1.0.0.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
DartCraft{Beta 0.2.10} [DartCraft] (DartCraft Beta 0.2.10.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded{1.6.2R2.7.1} [MineFactory Reloaded] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatAppliedEnergistics{1.6.2R2.7.1} [MFR Compat: Applied Energistics] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatAtum{1.6.2R2.7.1} [MFR Compat: Atum] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatBackTools{1.6.2R2.7.1} [MFR Compat: BackTools] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatBiomesOPlenty{1.6.2R2.7.1} [MFR Compat: Biomes O' Plenty] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatChococraft{1.6.2R2.7.1} [MFR Compat: Chococraft] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatExtraBiomes{1.6.2R2.7.1} [MFR Compat: ExtraBiomes] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatForestry{1.6.2R2.7.1} [MFR Compat: Forestry] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatForestryPre{1.6.2R2.7.1} [MFR Compat: Forestry (part 2)] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatIC2{1.6.2R2.7.1} [MFR Compat: IC2] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatMagicalCrops{1.6.2R2.7.1} [MFR Compat: Magical Crops] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatMystcraft{1.6.2R2.7.1} [MFR Compat: Mystcraft] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatPams{1.6.2R2.7.1} [MFR Compat: Pam's Mods] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatRailcraft{1.6.2R2.7.1} [MFR Compat: Railcraft] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatRP2{1.6.2R2.7.1} [MFR Compat: RP2] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatSufficientBiomes{1.6.2R2.7.1} [MFR Compat: Sufficient Biomes] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatThaumcraft{1.6.2R2.7.1} [MFR Compat: Thaumcraft] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatTwilightForest{1.6.2R2.7.1} [MFR Compat: TwilightForest] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatVanilla{1.6.2R2.7.1} [MFR Compat: Vanilla] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
MineFactoryReloaded|CompatXyCraft{1.6.2R2.7.1} [MFR Compat: XyCraft] (MineFactoryReloaded-2.7.1-36.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available
Profiler Position: N/A (disabled)
Vec3 Pool Size: 230 (12880 bytes; 0 MB) allocated, 91 (5096 bytes; 0 MB) used
Player Count: 1 / 8; [EntityPlayerMP['TheMapMakerX'/73, l='Test World', x=-844.50, y=56.00, z=807.50]]
Type: Integrated Server (map_client.txt)
Is Modded: Definitely; Client brand changed to 'fml,forge'