I'm aware it's probably due to an issue with memory allocation and block lag causing this problem, however since it is a crash none the less I figured I'd go ahead and post it. Everytime I chop the first block at the base of a sequoia the game crashes, once I relaunch and relog all is well until I go to another sequoia and do it again. ---- Minecraft Crash Report ---- // I bet Cylons wouldn't have this problem. Time: 5/9/13 10:09 AM Description: Exception in server tick loop java.lang.NoClassDefFoundError: net/minecraft/world/CallableLvl1 at net.minecraft.world.World.func_72821_m(World.java:856) at net.minecraft.world.World.func_72898_h(World.java:783) at net.minecraft.world.World.func_72851_f(World.java:735) at net.minecraft.world.World.func_72832_d(World.java:567) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:278) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.scanLogs(BlockLogNatural.java:265) at TFC.Blocks.BlockLogNatural.ProcessTree(BlockLogNatural.java:211) at TFC.Blocks.BlockLogNatural.func_71893_a(BlockLogNatural.java:152) at net.minecraft.item.ItemInWorldManager.func_73084_b(ItemInWorldManager.java:334) at net.minecraft.item.ItemInWorldManager.func_73082_a(ItemInWorldManager.java:238) at net.minecraft.network.NetServerHandler.func_72510_a(NetServerHandler.java:500) at net.minecraft.network.packet.Packet14BlockDig.func_73279_a(SourceFile:46) at net.minecraft.network.MemoryConnection.func_74428_b(MemoryConnection.java:89) at net.minecraft.network.NetServerHandler.func_72570_d(NetServerHandler.java:134) at net.minecraft.network.NetworkListenThread.func_71747_b(NetworkListenThread.java:53) at net.minecraft.server.integrated.IntegratedServerListenThread.func_71747_b(IntegratedServerListenThread.java:109) at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:674) at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:570) at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:127) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:468) at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573) 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 (x86) version 6.1 Java Version: 1.7.0_09, Oracle Corporation Java VM Version: Java HotSpot Client VM (mixed mode), Oracle Corporation Memory: 173256584 bytes (165 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB) JVM Flags: 2 total; -Xmx1024M -Xms512M AABB Pool Size: 5739 (321384 bytes; 0 MB) allocated, 5389 (301784 bytes; 0 MB) used Suspicious classes: FML and Forge are installed IntCache: cache: 0, tcache: 7469, allocated: 1, tallocated: 33 FML: MCP v7.44 FML v5.1.13.629 Minecraft Forge 7.7.1.629 4 mods loaded, 4 mods active mcp [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available FML [Forge Mod Loader] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available Forge [Minecraft Forge] (coremods) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available TerraFirmaCraft [TerraFirmaCraft] (TFCraft-Universal-Core-B2-Build76Hotfix15.zip) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available Profiler Position: N/A (disabled) Vec3 Pool Size: 1281 (71736 bytes; 0 MB) allocated, 1200 (67200 bytes; 0 MB) used Player Count: 1 / 8; [EntityPlayerMP['SirAdam87'/206, l='TeraNova', x=-50.93, y=152.00, z=-12803.49]] Type: Integrated Server (map_client.txt) Is Modded: Definitely; Client brand changed to 'fml,forge'