I start minecraft single player, and minecraft crashed.

• • • • • Minecraft Crash Report ----
          // Daisy, daisy...

Time: 19.03.14 22:35
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: Day Of The Heist
Level Name: Day Of The Heist
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 7 (x86) version 6.1
Java Version: 1.7.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 56754512 bytes (54 MB) / 98037760 bytes (93 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: Intel(R) HD Graphics GL version 3.1.0 - Build 8.15.10.2752, Intel
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: Русский (Россия)
Profiler Position: N/A (disabled)*
Anisotropic Filtering: Off (1)