World Generation Problems

When I try to launch or create a new world, my game output comes up with the following error messages:

Preparing spawn area: 6%
16:49:45	net.minecraft.server.MinecraftServer	Encountered an unexpected exception
java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: Tried to access a block entity before it was created. b{x=161, y=70, z=1}
	at net.minecraft.server.MinecraftServer.i_(SourceFile:395)
	at cvl.a(SourceFile:115)
	at cvl.d(SourceFile:131)
	at net.minecraft.server.MinecraftServer.run(SourceFile:503)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.concurrent.ExecutionException: java.lang.RuntimeException: Tried to access a block entity before it was created. b{x=161, y=70, z=1}
	at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2272)
	at net.minecraft.server.MinecraftServer.i_(SourceFile:393)
	... 4 more
Caused by: java.lang.RuntimeException: Tried to access a block entity before it was created. b{x=161, y=70, z=1}
	at sf.f(SourceFile:181)
	at bbs.a(SourceFile:230)
	at bfj.d(SourceFile:158)
	at axn.d(SourceFile:483)
	at bfj.a(SourceFile:54)
	at axn.e(SourceFile:492)
	at bfj.b(SourceFile:58)
	at bqk.b(SourceFile:57)
	at bqk.a(SourceFile:124)
	at bqn.a(SourceFile:63)
	at sq.a(SourceFile:24)
	at sm.a(SourceFile:34)
	at bgq.a(SourceFile:89)
	at sr.a(SourceFile:54)
	at sr.a(SourceFile:23)
	at zo$a.a(SourceFile:143)
	at zo$a$$Lambda$878/114583575.apply(Unknown Source)
	at java.util.concurrent.CompletableFuture$AsyncApply.exec(CompletableFuture.java:501)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:902)
	at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1689)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1644)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
16:49:45	net.minecraft.server.MinecraftServer	This crash report has been saved to: C:\Users\jerem\AppData\Roaming\.minecraft\crash-reports\crash-2018-02-13_16.49.45-server.txt

The following message also comes up:

Stopping server
16:49:45	net.minecraft.server.MinecraftServer	Saving players
16:49:45	net.minecraft.server.MinecraftServer	Saving worlds
16:49:45	net.minecraft.server.MinecraftServer	Saving chunks for level 'Debug Mode'/overworld
16:49:45	net.minecraft.server.MinecraftServer	Saving chunks for level 'Debug Mode'/the_nether
16:49:45	net.minecraft.server.MinecraftServer	Saving chunks for level 'Debug Mode'/the_end
16:49:45	rz	Couldn't stop taskManager
java.util.concurrent.ExecutionException: java.lang.RuntimeException: Tried to access a block entity before it was created. b{x=161, y=70, z=1}
	at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:2237)
	at zo.b(SourceFile:92)
	at zq.a(SourceFile:25)
	at rz.close(SourceFile:267)
	at atm.close(SourceFile:2020)
	at sa.close(SourceFile:1067)
	at net.minecraft.server.MinecraftServer.j_(SourceFile:475)
	at cvl.j_(SourceFile:311)
	at net.minecraft.server.MinecraftServer.run(SourceFile:566)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: Tried to access a block entity before it was created. b{x=161, y=70, z=1}
	at sf.f(SourceFile:181)
	at bbs.a(SourceFile:230)
	at bfj.d(SourceFile:158)
	at axn.d(SourceFile:483)
	at bfj.a(SourceFile:54)
	at axn.e(SourceFile:492)
	at bfj.b(SourceFile:58)
	at bqk.b(SourceFile:57)
	at bqk.a(SourceFile:124)
	at bqn.a(SourceFile:63)
	at sq.a(SourceFile:24)
	at sm.a(SourceFile:34)
	at bgq.a(SourceFile:89)
	at sr.a(SourceFile:54)
	at sr.a(SourceFile:23)
	at zo$a.a(SourceFile:143)
	at zo$a$$Lambda$878/114583575.apply(Unknown Source)
	at java.util.concurrent.CompletableFuture$AsyncApply.exec(CompletableFuture.java:501)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:902)
	at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1689)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1644)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

What does this mean? How can I fix it?