Modded Server error! Need help ASAP!

Recently I have been setting up a modded server. I correctly got FML installed and the server worked. Then I made a little "mod pack" and got the configs fixed. These mods are all universal/client-side. I got everything loaded up into the server and it went fine. At first. Then all of sudden I got an error. Not sure (exactly) what it's about. Can anyone tell me? ---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 4/13/13 10:15 PM
Description: Exception in server tick loop

cpw.mods.fml.common.LoaderException: java.lang.NoSuchFieldError: textureSheet
at cpw.mods.fml.common.LoadController.transition(LoadController.java:142)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:514)
at cpw.mods.fml.server.FMLServerHandler.beginServerLoading(FMLServerHandler.java:85)
at cpw.mods.fml.common.FMLCommonHandler.onServerStart(FMLCommonHandler.java:352)
at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:69)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:429)
at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573)
Caused by: java.lang.NoSuchFieldError: textureSheet
at net.minecraftforge.liquids.LiquidStack.<init>(LiquidStack.java:140)
at net.minecraftforge.liquids.LiquidStack.<init>(LiquidStack.java:31)
at ic2.core.IC2.load(IC2.java:975)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:515)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:165)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:98)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:513)
... 5 more


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

-- System Details --
Details:
Minecraft Version: 1.5.1
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_07, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 841509240 bytes (802 MB) / 1031143424 bytes (983 MB) up to 1031143424 bytes (983 MB)
JVM Flags: 2 total; -Xmx1024M -Xms1024M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v7.44 FML v5.1.10.620 Minecraft Forge 7.7.1.620 21 mods loaded, 21 mods active
mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized
FML [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized
Forge [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized
CodeChickenCore [CodeChicken Core] (coremods) Unloaded->Constructed->Pre-initialized
BuildCraft|Core [BuildCraft] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Pre-initialized
BuildCraft|Transport [BC Transport] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Pre-initialized
BuildCraft|Silicon [BC Silicon] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Pre-initialized
IC2 [IndustrialCraft 2] (industrialcraft-2_1.115.290-lf.jar) Unloaded->Constructed->Errored
AppliedEnergistics [Applied Energistics] (appeng-rv10-d.zip) Unloaded->Constructed->Pre-initialized
ArsMagica [Ars Magica] (ArsMagica_5.50.003.zip) Unloaded->Constructed->Pre-initialized
BuildCraft|Builders [BC Builders] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Pre-initialized
BuildCraft|Energy [BC Energy] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Errored
BuildCraft|Factory [BC Factory] (buildcraft-A-3.5.0.jar) Unloaded->Constructed->Pre-initialized
FlansMod [Flan's Mod] (Flans Mod 2.3 for Minecraft 1.5.1 Universal.zip) Unloaded->Constructed->Pre-initialized
Forestry [Forestry for Minecraft] (forestry-A-2.1.2.9.jar) Unloaded->Constructed->Pre-initialized
iChunUtil [iChunUtil] (iChunUtil1.0.0.zip) Unloaded->Constructed->Pre-initialized
IronChest [Iron Chest] (ironchest-universal-1.5-5.2.1.284.zip) Unloaded->Constructed->Pre-initialized
MoreSwordsMod [More Swords Mod] (More Swords Mod 2.4.2 For 1.5.1.jar) Unloaded->Constructed->Pre-initialized
Natura [Natura] (Natura_1.5.1_2.0.9.jar) Unloaded->Constructed->Pre-initialized
PortalGun [PortalGun] (PortalGun1.5.1.zip) Unloaded->Constructed->Pre-initialized
TConstruct [Tinkers' Construct] (TConstruct_1.5.1_1.2.28.jar) Unloaded->Constructed->Errored
Profiler Position: N/A (disabled)
Is Modded: Definitely; Server brand changed to 'fml'
Type: Dedicated Server (map_server.txt)

Mod list:

U = Universal
C = Clientside

U - Applied Energistecs
U - ArsMagica
C - Backtools
U - Buildcraft
U - Flans Mod
U - Forestry
U - iChunutil
U - IC2
U - Ironchest
U - More Swords
U - Natura
U - Portalgun
U - Tinkers Construct
U/C - NEI
U - Chicken Bones core

All mods were downloaded a few hours ago. All up to date 1.5.1