it crashed when loading a world with the official caves and cliffs preview datapack

and i used the vanilla launcher btw

crash log

---- Minecraft Crash Report -------- Minecraft Crash Report ----// Would you like a cupcake?
Time: 14-4-21 20:02Description: Unexpected error
java.lang.IllegalStateException: Missing: ResourceKey[minecraft:worldgen/biome / minecraft:plains] at gr.d(SourceFile:405) at ehy.a(SourceFile:543) at bwa.b(SourceFile:67) at bxf.a(SourceFile:58) at bwy.a(SourceFile:32) at bwa.u(SourceFile:39) at ehy.a(SourceFile:320) at ehy.c(SourceFile:275) at dun.q(SourceFile:1656) at dun.e(SourceFile:1042) at dun.e(SourceFile:700) at net.minecraft.client.main.Main.main(SourceFile:217)

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– Head --Thread: Render threadStacktrace: at gr.d(SourceFile:405) at ehy.a(SourceFile:543) at bwa.b(SourceFile:67) at bxf.a(SourceFile:58) at bwy.a(SourceFile:32) at bwa.u(SourceFile:39) at ehy.a(SourceFile:320) at ehy.c(SourceFile:275)
– Affected level --Details: All players: 1 total; [ekw['jarn123'/122, l='ClientLevel', x=574.27, y=86.14, z=536.33]] Chunk stats: 841, 0 Level dimension: minecraft:overworld Level spawn location: World: (192,63,-256), Section: (at 0,15,0 in 12,3,-16; chunk contains blocks 192,-64,-256 to 207,319,-241), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,-64,-512 to 511,319,-1) Level time: 38972 game time, 26779 day time Server brand: vanilla Server type: Integrated singleplayer serverStacktrace: at ehy.a(SourceFile:370) at dun.c(SourceFile:2259) at dun.e(SourceFile:724) at net.minecraft.client.main.Main.main(SourceFile:217)
– System Details --Details: Minecraft Version: 21w15a Minecraft Version ID: 21w15a Operating System: Windows 7 (amd64) version 6.1 Java Version: 1.8.0_51, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 817746280 bytes (779 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB) CPUs: 8 JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M Launched Version: 21w15a Backend library: LWJGL version 3.2.2 build 10 Backend API: ATI Radeon HD 5400 Series GL version 3.2.13417 Core Profile Forward-Compatible Context 15.301.1901.0, ATI Technologies Inc. GL Caps: Using framebuffer using OpenGL 3.2 Using VBOs: Yes Is Modded: Probably not. Jar signature remains and client brand is untouched. Type: Client (map_client.txt) Graphics mode: fancy Resource Packs: vanilla Current Language: English (US) CPU: 8x Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz