---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 12/20/17 6:21 PM
Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world
at net.minecraft.world.chunk.storage.ExtendedBlockStorage.func_76670_c(ExtendedBlockStorage.java:88)
at net.minecraft.world.chunk.Chunk.func_177413_a(Chunk.java:652)
at net.minecraft.world.World.func_175642_b(World.java:858)
at net.minecraft.world.World.func_180500_c(World.java:2839)
at net.minecraft.world.World.func_175664_x(World.java:2757)
at net.minecraft.world.chunk.Chunk.func_76594_o(Chunk.java:1279)
at net.minecraft.world.WorldServer.func_147456_g(WorldServer.java:398)
at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:225)
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:754)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:666)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:524)
at java.lang.Thread.run(Thread.java:745)

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

-- Head --
Thread: Server thread
Stacktrace:
at net.minecraft.world.chunk.storage.ExtendedBlockStorage.func_76670_c(ExtendedBlockStorage.java:88)
at net.minecraft.world.chunk.Chunk.func_177413_a(Chunk.java:652)
at net.minecraft.world.World.func_175642_b(World.java:858)
at net.minecraft.world.World.func_180500_c(World.java:2839)
at net.minecraft.world.World.func_175664_x(World.java:2757)
at net.minecraft.world.chunk.Chunk.func_76594_o(Chunk.java:1279)
at net.minecraft.world.WorldServer.func_147456_g(WorldServer.java:398)
at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:225)

-- Affected level --
Details:
Level name: New World
All players: 1 total; [EntityPlayerMP['Stervil'/762, l='New World', x=107.59, y=101.05, z=234.67]]
Chunk stats: ServerChunkCache: 661 Drop: 0
Level seed: 5967517864726561566
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (208,64,256), Chunk: (at 0,4,0 in 13,16; contains blocks 208,0,256 to 223,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 2798 game time, 2798 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 166615 (now: false), thunder time: 151998 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:754)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:666)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:524)
at java.lang.Thread.run(Thread.java:745)

-- System Details --
Details:
Minecraft Version: 1.12.2
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 260989928 bytes (248 MB) / 754974720 bytes (720 MB) up to 2147483648 bytes (2048 MB)
JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
FML: MCP 9.42 Powered by Forge 14.23.0.2512 6 mods loaded, 6 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored

| State     | ID                  | Version      | Source                             | Signature                                |
|:--------- |:------------------- |:------------ |:---------------------------------- |:---------------------------------------- |
| UCHIJAAAA | minecraft           | 1.12.2       | minecraft.jar                      | None                                     |
| UCHIJAAAA | mcp                 | 9.42         | minecraft.jar                      | None                                     |
| UCHIJAAAA | FML                 | 8.0.99.99    | forge-1.12.2-14.23.0.2512.jar      | e3c3d50c7c986df74c645c0ac54639741c90a557 |
| UCHIJAAAA | forge               | 14.23.0.2512 | forge-1.12.2-14.23.0.2512.jar      | e3c3d50c7c986df74c645c0ac54639741c90a557 |
| UCHIJAAAA | mercurius_updater   | 1.0          | MercuriusUpdater-1.12.2.jar        | None                                     |
| UCHIJAAAA | appliedenergistics2 | rv5-beta-1   | appliedenergistics2-rv5-beta-1.jar | None                                     |

Loaded coremods (and transformers): 
GL info: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
AE2 Version: beta rv5-beta-1 for Forge 14.23.0.2491
AE2 Integration: IC2:OFF, RC:OFF, MFR:OFF, Waila:OFF, InvTweaks:OFF, JEI:OFF, Mekanism:OFF, OpenComputers:OFF, THE_ONE_PROBE:OFF, TESLA:OFF
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [EntityPlayerMP['Stervil'/762, l='New World', x=107.59, y=101.05, z=234.67]]
Type: Integrated Server (map_client.txt)
Is Modded: Definitely; Client brand changed to 'fml,forge'

Description

When I try to save an area too big (bigger than 24 blocks in all directions) I get an instant crash of the client if SP or the server if MP, when it should save the area.

Environment

Crash reproduced in both, SinglePlayer and Server, instances.
tried in my modpack with another 158 mods, and also with the AE2 instaled alone.

• Minecraft Version: 1.12.2
• AE2 Version: rv5 - stable 3
• Forge Version: 14.23.1.2566
  14.23.1.2560
  14.23.1.2555
  14.23.0.2512
  14.23.0.2485

appliedenergistics2-rv5-beta-1.jar

Just to be sure, can you please reproduce this with the newest AE2 and forge?

Also, a log with debug enabled (in appliedenergistic2.cfg) would be helpful.