Hello, I'm from Germany and can speak bad English and Google Translate has to help me; D

So, I have a single player world with Forge / Mods
-World Edit
Chisel and bits
-Liquid Bounce (Hack Client, for faster build, move)

I accidentally used a wrong version and I am in this world gejoint, after I noticed that all mod blocks were gone, I have the Forge version again selected, however, when trying to open the world Crasht Minecraft.
The Crash Report:

---- Minecraft Crash Report ----

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

// Don't be sad, have a hug! <3

Time: 12.04.18 14:36
Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
at net.minecraft.world.WorldServer.func_180497_b(WorldServer.java:519)
at net.minecraft.world.chunk.storage.AnvilChunkLoader.loadEntities(AnvilChunkLoader.java:529)
at net.minecraftforge.common.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:41)
at net.minecraftforge.common.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:12)
at net.minecraftforge.common.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:344)
at net.minecraftforge.common.util.AsynchronousExecutor.getSkipQueue(AsynchronousExecutor.java:302)
at net.minecraftforge.common.chunkio.ChunkIOExecutor.syncChunkLoad(ChunkIOExecutor.java:12)
at net.minecraft.world.gen.ChunkProviderServer.loadChunk(ChunkProviderServer.java:109)
at net.minecraft.world.gen.ChunkProviderServer.func_73158_c(ChunkProviderServer.java:84)
at net.minecraft.server.MinecraftServer.func_71222_d(MinecraftServer.java:307)
at net.minecraft.server.integrated.IntegratedServer.func_71247_a(IntegratedServer.java:109)
at net.minecraft.server.integrated.IntegratedServer.func_71197_b(IntegratedServer.java:123)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:441)
at java.lang.Thread.run(Thread.java:745)


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

-- System Details --
Details:
Minecraft Version: 1.8.9
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: 255549776 bytes (243 MB) / 553648128 bytes (528 MB) up to 1073741824 bytes (1024 MB)
JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP 9.19 Powered by Forge 11.15.1.2318 5 mods loaded, 5 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
UCHIJAA mcp{9.19} [Minecraft Coder Pack] (minecraft.jar)
UCHIJAA FML{8.0.99.99} [Forge Mod Loader] (forge-1.8.9-11.15.1.2318-1.8.9.jar)
UCHIJAA Forge{11.15.1.2318} [Minecraft Forge] (forge-1.8.9-11.15.1.2318-1.8.9.jar)
UCHIJAA chiselsandbits{8.12} [Chisels & Bits] (chiselsandbits-8.12.jar)
UCHIJAA worldedit{6.1.1} [WorldEdit] (worldedit-forge-mc1.8.9-6.1.1.jar)
Loaded coremods (and transformers):
GL info: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
Profiler Position: N/A (disabled)
Player Count: 0 / 8; []
Type: Integrated Server (map_client.txt)
Is Modded: Definitely; Client brand changed to 'fml,forge'