Minecraft crashes when loading a World: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1

Minecraft 14w11b Crashes when selecting a World and then trying to play it

*What I expected to happen was...
For the world to load up like normal

*What actually happened was...
It goes to the world generation screen and then crashes

Steps to Reproduce:
1. Start up Minecraft 14w11b
2. Select a world and select play world, or create a world
3. The game crashes

Here's the crash report:

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

Time: 16/03/14 1:59 PM
Description: Starting integrated server

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
	at com.google.gson.Gson.fromJson(Gson.java:815)
	at com.google.gson.Gson.fromJson(Gson.java:768)
	at oy.b(SourceFile:141)
	at oy.<init>(SourceFile:43)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
	at cek.<init>(SourceFile:34)
	at bfr.a(SourceFile:1701)
	at bja.e(SourceFile:165)
	at bja.a(SourceFile:128)
	at biz.a(SourceFile:180)
	at biz.d(SourceFile:242)
	at biz.k(SourceFile:219)
	at bfr.p(SourceFile:1387)
	at bfr.ai(SourceFile:801)
	at bfr.f(SourceFile:755)
	at net.minecraft.client.main.Main.main(SourceFile:121)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 1
	at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:338)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:79)
	at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:60)
	at com.google.gson.Gson.fromJson(Gson.java:803)
	... 15 more


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

-- Head --
Stacktrace:
	at com.google.gson.Gson.fromJson(Gson.java:815)
	at com.google.gson.Gson.fromJson(Gson.java:768)
	at oy.b(SourceFile:141)
	at oy.<init>(SourceFile:43)
	at net.minecraft.server.MinecraftServer.<init>(SourceFile:120)
	at cek.<init>(SourceFile:34)

-- Starting integrated server --
Details:
	Level ID: 1_8 Snapshot
	Level Name: 1.8 Showcase
Stacktrace:
	at bfr.a(SourceFile:1701)
	at bja.e(SourceFile:165)
	at bja.a(SourceFile:128)
	at biz.a(SourceFile:180)
	at biz.d(SourceFile:242)
	at biz.k(SourceFile:219)

-- Affected screen --
Details:
	Screen name: bjk
Stacktrace:
	at bfr.p(SourceFile:1387)
	at bfr.ai(SourceFile:801)
	at bfr.f(SourceFile:755)
	at net.minecraft.client.main.Main.main(SourceFile:121)

-- System Details --
Details:
	Minecraft Version: 14w11b
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 56150808 bytes (53 MB) / 96677888 bytes (92 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Launched Version: 14w11b
	LWJGL: 2.9.1
	OpenGL: AMD Radeon HD 8610G + 8500M Dual Graphics GL version 4.3.12618 Compatibility Profile Context 13.251.0.0, ATI Technologies Inc.
	GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

	Is Modded: Probably not. Jar signature remains and client brand is untouched.
	Type: Client (map_client.txt)
	Resource Packs: []
	Current Language: English (US)
	Profiler Position: N/A (disabled)
	Anisotropic Filtering: Off (1)