[17:15:55] [Server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: com.google.common.util.concurrent.UncheckedExecutionException: java.lang.IllegalArgumentException: Invalid loot table name 'chests:simple_dungeon.json' (can't contain periods)
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:46) [15w44a.jar:?]
	at net.minecraft.server.MinecraftServer.D(SourceFile:590) [15w44a.jar:?]
	at net.minecraft.server.MinecraftServer.C(SourceFile:546) [15w44a.jar:?]
	at bxw.C(SourceFile:154) [15w44a.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:450) [15w44a.jar:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
Caused by: com.google.common.util.concurrent.UncheckedExecutionException: java.lang.IllegalArgumentException: Invalid loot table name 'chests:simple_dungeon.json' (can't contain periods)
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2201) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache.get(LocalCache.java:3934) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4827) ~[guava-17.0.jar:?]
	at azu.a(SourceFile:46) ~[15w44a.jar:?]
	at ye.A(SourceFile:243) ~[15w44a.jar:?]
	at ye.a(SourceFile:54) ~[15w44a.jar:?]
	at qh.a(SourceFile:25) ~[15w44a.jar:?]
	at qh.a(SourceFile:20) ~[15w44a.jar:?]
	at ye.N(SourceFile:135) ~[15w44a.jar:?]
	at yb.a(SourceFile:190) ~[15w44a.jar:?]
	at zo.f(SourceFile:1069) ~[15w44a.jar:?]
	at ls.f(SourceFile:1030) ~[15w44a.jar:?]
	at mc.a(SourceFile:907) ~[15w44a.jar:?]
	at is.a(SourceFile:68) ~[15w44a.jar:?]
	at is.a(SourceFile:12) ~[15w44a.jar:?]
	at fh$1.run(SourceFile:13) ~[15w44a.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at g.a(SourceFile:45) ~[15w44a.jar:?]
	... 5 more
Caused by: java.lang.IllegalArgumentException: Invalid loot table name 'chests:simple_dungeon.json' (can't contain periods)
	at azu$a.a(SourceFile:61) ~[15w44a.jar:?]
	at azu$a.load(SourceFile:56) ~[15w44a.jar:?]
	at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3524) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2317) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2280) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache.get(LocalCache.java:3934) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3938) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4821) ~[guava-17.0.jar:?]
	at com.google.common.cache.LocalCache$LocalLoadingCache.getUnchecked(LocalCache.java:4827) ~[guava-17.0.jar:?]
	at azu.a(SourceFile:46) ~[15w44a.jar:?]
	at ye.A(SourceFile:243) ~[15w44a.jar:?]
	at ye.a(SourceFile:54) ~[15w44a.jar:?]
	at qh.a(SourceFile:25) ~[15w44a.jar:?]
	at qh.a(SourceFile:20) ~[15w44a.jar:?]
	at ye.N(SourceFile:135) ~[15w44a.jar:?]
	at yb.a(SourceFile:190) ~[15w44a.jar:?]
	at zo.f(SourceFile:1069) ~[15w44a.jar:?]
	at ls.f(SourceFile:1030) ~[15w44a.jar:?]
	at mc.a(SourceFile:907) ~[15w44a.jar:?]
	at is.a(SourceFile:68) ~[15w44a.jar:?]
	at is.a(SourceFile:12) ~[15w44a.jar:?]
	at fh$1.run(SourceFile:13) ~[15w44a.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at g.a(SourceFile:45) ~[15w44a.jar:?]
	... 5 more