I got a Bug Report for you Speiger, it is very similar to the one where I caused a Block Update and shit looped around, but this time it is YOU causing a Block Update with Sand and Gravel that is being the issue.
Here is the original Post: https://forum.industrial-craft.net/thread/7156/?postID=215622#post215622
net.minecraft.util.ReportedException: Exception getting block type in world
at net.minecraft.world.WorldServer.func_72955_a(WorldServer.java:568)
at pregenerator.impl.processor.ChunkHelper.cleanUp(ChunkHelper.java:84)
at pregenerator.impl.processor.ChunkProcess.onTickStart(ChunkProcess.java:114)
at pregenerator.impl.processor.ChunkProcessor.onServerTickEvent(ChunkProcessor.java:94)
at cpw.mods.fml.common.eventhandler.ASMEventHandler_65_ChunkProcessor_onServerTickEvent_ServerTickEvent.invoke(.dynamic)
at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54)
at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140)
at cpw.mods.fml.common.FMLCommonHandler.onPostServerTick(FMLCommonHandler.java:247)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:590)
at fastcraft.u.a(F:289)
at fastcraft.H.aq(F:36)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:396)
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)
Caused by: java.lang.ClassCastException: gregapi.block.multitileentity.example.MultiTileEntityChest cannot be cast to net.minecraft.tileentity.TileEntityChest
at net.minecraft.world.gen.feature.WorldGenDungeons.func_76484_a(WorldGenDungeons.java:129)
at net.minecraft.world.gen.ChunkProviderGenerate.func_73153_a(ChunkProviderGenerate.java:418)
at net.minecraft.world.gen.ChunkProviderServer.func_73153_a(ChunkProviderServer.java:279)
at net.minecraft.world.chunk.Chunk.func_76624_a(Chunk.java:1040)
at net.minecraft.world.gen.ChunkProviderServer.originalLoadChunk(ChunkProviderServer.java:190)
at net.minecraft.world.gen.ChunkProviderServer.loadChunk(ChunkProviderServer.java:131)
at net.minecraft.world.gen.ChunkProviderServer.func_73158_c(ChunkProviderServer.java:101)
at net.minecraft.world.gen.ChunkProviderServer.func_73154_d(ChunkProviderServer.java:199)
at net.minecraft.world.World.func_72964_e(World.java:419)
at net.minecraft.world.World.func_147439_a(World.java:345)
at net.minecraft.world.World.func_147460_e(World.java:693)
at net.minecraft.world.World.func_147459_d(World.java:648)
at net.minecraft.world.World.func_147444_c(World.java:613)
at net.minecraft.world.World.markAndNotifyBlock(World.java:488)
at net.minecraft.world.World.func_147465_d(World.java:466)
at net.minecraft.world.World.func_147468_f(World.java:573)
at net.minecraft.block.BlockFalling.func_149830_m(BlockFalling.java:61)
at net.minecraft.block.BlockFalling.func_149674_a(BlockFalling.java:40)
at net.minecraft.world.WorldServer.func_72955_a(WorldServer.java:550)
at pregenerator.impl.processor.ChunkHelper.cleanUp(ChunkHelper.java:84)
at pregenerator.impl.processor.ChunkProcess.onTickStart(ChunkProcess.java:114)
at pregenerator.impl.processor.ChunkProcessor.onServerTickEvent(ChunkProcessor.java:94)
at cpw.mods.fml.common.eventhandler.ASMEventHandler_65_ChunkProcessor_onServerTickEvent_ServerTickEvent.invoke(.dynamic)
at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54)
at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140)
at cpw.mods.fml.common.FMLCommonHandler.onPostServerTick(FMLCommonHandler.java:247)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:590)