I've recently tried to re-install TFC after a long absence of playing, and it will not work for me. I'm having a similar issue to the other guy that posted today. The Mojang logo pops up and then the game crashes. I don't understand the coding to well, but from what I can tell the main difference is that his was a null point error and mine is an illegal argument error. Here's the crash report: java.lang.IllegalArgumentException: Slot 173 is already occupied by net.minecraft.block.Block@1434736 when adding TFC.Blocks.Flora.BlockFruitLeaves@1f84171at net.minecraft.block.Block.<init>(Block.java:349)at net.minecraft.block.BlockContainer.<init>(SourceFile:9)at TFC.Blocks.BlockTerraContainer.<init>(BlockTerraContainer.java:23)at TFC.Blocks.Flora.BlockFruitLeaves.<init>(BlockFruitLeaves.java:42)at TFC.TFCBlocks.LoadBlocks(TFCBlocks.java:582)at TFC.TerraFirmaCraft.preInit(TerraFirmaCraft.java:127)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:545)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:313)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.sendEventToModContainer(LoadController.java:201)at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:181)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:313)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:112)at cpw.mods.fml.common.Loader.loadMods(Loader.java:522)at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:183)at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:473)at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:808)at net.minecraft.client.main.Main.main(SourceFile:101)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 net.minecraft.launchwrapper.Launch.launch(Launch.java:131)at net.minecraft.launchwrapper.Launch.main(Launch.java:27)A detailed walkthrough of the error, its code path and all known details is as follows:----------------------------------------------------------------------------------------- Head --Stacktrace:at net.minecraft.block.Block.<init>(Block.java:349)at net.minecraft.block.BlockContainer.<init>(SourceFile:9)at TFC.Blocks.BlockTerraContainer.<init>(BlockTerraContainer.java:23)at TFC.Blocks.Flora.BlockFruitLeaves.<init>(BlockFruitLeaves.java:42)at TFC.TFCBlocks.LoadBlocks(TFCBlocks.java:582)at TFC.TerraFirmaCraft.preInit(TerraFirmaCraft.java:127)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:545)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:313)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.sendEventToModContainer(LoadController.java:201)at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:181)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:313)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:112)at cpw.mods.fml.common.Loader.loadMods(Loader.java:522)at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:183)at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:473)-- Initialization --Details:Stacktrace:at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:808)at net.minecraft.client.main.Main.main(SourceFile:101)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 net.minecraft.launchwrapper.Launch.launch(Launch.java:131)at net.minecraft.launchwrapper.Launch.main(Launch.java:27)-- System Details --Details:Minecraft Version: 1.6.4Operating System: Windows 8 (x86) version 6.2Java Version: 1.7.0_60, Oracle CorporationJava VM Version: Java HotSpot Client VM (mixed mode, sharing), Oracle CorporationMemory: 20192176 bytes (19 MB) / 124436480 bytes (118 MB) up to 518979584 bytes (494 MB)JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512MAABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) usedSuspicious classes: FML and Forge are installedIntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0FML: MCP v8.11 FML v6.4.49.965 Minecraft Forge 9.11.1.965 5 mods loaded, 5 mods activemcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initializedFML{6.4.49.965} [Forge Mod Loader] (minecraftforge-9.11.1.965.jar) Unloaded->Constructed->Pre-initializedForge{9.11.1.965} [Minecraft Forge] (minecraftforge-9.11.1.965.jar) Unloaded->Constructed->Pre-initializedtfc_coremod{0.78.17} [TFC[coremod]] (minecraft.jar) Unloaded->Constructed->Pre-initializedterrafirmacraft{0.78.17} [TerraFirmaCraft] (TFC-0.78.17.jar) Unloaded->Constructed->ErroredLaunched Version: 1.6.4-Forge9.11.1.965LWJGL: 2.9.0OpenGL: ASUS HD7670 Series GL version 4.2.11762 Compatibility Profile Context, ATI Technologies Inc.Is Modded: Definitely; Client brand changed to 'fml,forge'Type: Client (map_client.txt)Resource Pack: DefaultCurrent Language: English (US)Profiler Position: N/A (disabled)Vec3 Pool Size: ~~ERROR~~ NullPointerException: null