Put the summary of the bug you're having here

I thought i was going to load up the custom map i installed.

What ended up happening was an instant crash.

this is what the crash report says, and i have no mods installed! I can't fix the problem because i can't read coding like this.

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

– Head –
Stacktrace:
at java.nio.Buffer.checkIndex(Buffer.java:512)
at java.nio.DirectIntBufferU.get(DirectIntBufferU.java:248)
at bma.a(SourceFile:271)
at bma.a(SourceFile:220)
at bao.a(SourceFile:1694)
at bao.a(SourceFile:1652)
at bjb.a(SourceFile:125)
at hd.a(SourceFile:70)
at hd.a(SourceFile:13)
at ej.a(SourceFile:174)

– Affected level –
Details:
Level name: MpServer
All players: 0 total; []
Chunk stats: MultiplayerChunkCache: 0, 0
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: World: (8,64,8), Chunk: (at 8,4,8 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 0 game time, 0 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Forced entities: 0 total; []
Retry entities: 0 total; []
Server brand: ~_ERROR~ NullPointerException: null
Server type: Integrated singleplayer server
Stacktrace:
at bjf.a(SourceFile:289)
at bao.b(SourceFile:1972)
at bao.f(SourceFile:742)
at net.minecraft.client.main.Main.main(SourceFile:148)

– System Details –
Details:
Minecraft Version: 1.7.10
Operating System: Mac OS X (x86_64) version 10.11
Java Version: 1.6.0_65, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 18063976 bytes (17 MB) / 176230400 bytes (168 MB) up to 2134114304 bytes (2035 MB)
JVM Flags: 5 total; -Xmx2G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
Launched Version: 1.7.10
LWJGL: 2.9.1
OpenGL: Intel(R) Iris(TM) Graphics 6100 GL version 2.1 INTEL-10.8.70, Intel Inc.
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because ARB_framebuffer_object 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)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)