Cannot log in my own unmodded minecraft server but if I download and create a brand new server I can join.

What I expected to happen was...:
Log in

What actually happened was...:
Didn't log in, said connection lost internal server error, then everytime after it would have the internal expection. netty something.

Steps to Reproduce:
1. Log in
2. Internal server error

Full bug report below:
---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 1/4/14 9:59 AM
Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world
at atu.a(SourceFile:86)
at apq.a(SourceFile:403)
at ml.a(SourceFile:160)
at aoo.a(SourceFile:778)
at ml.c(SourceFile:95)
at ml.d(SourceFile:108)
at afs.e(SourceFile:311)
at agf.a(SourceFile:21)
at agf.a(SourceFile:77)
at mm.b(SourceFile:117)
at net.minecraft.server.MinecraftServer.u(SourceFile:502)
at lm.u(SourceFile:265)
at net.minecraft.server.MinecraftServer.t(SourceFile:440)
at net.minecraft.server.MinecraftServer.run(SourceFile:357)
at lb.run(SourceFile:616)

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

– Head –
Stacktrace:
at atu.a(SourceFile:86)
at apq.a(SourceFile:403)
at ml.a(SourceFile:160)
at aoo.a(SourceFile:778)
at ml.c(SourceFile:95)
at ml.d(SourceFile:108)
at afs.e(SourceFile:311)
at agf.a(SourceFile:21)
at agf.a(SourceFile:77)
at mm.b(SourceFile:117)

– Affected level –
Details:
Level name:
All players: 1 total; [mp['FlossyDSM'/527, l='', x=-4155.70, y=93.00, z=3855.04]]
Chunk stats: ServerChunkCache: 804 Drop: 0
Level seed: 7604068753927131681
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (0,64,0), Chunk: (at 0,4,0 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: 6969798 game time, 25666 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 114411 (now: false), thunder time: 2059 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.u(SourceFile:502)
at lm.u(SourceFile:265)
at net.minecraft.server.MinecraftServer.t(SourceFile:440)
at net.minecraft.server.MinecraftServer.run(SourceFile:357)
at lb.run(SourceFile:616)

– System Details –
Details:
Minecraft Version: 1.7.4
Operating System: Windows 8 (amd64) version 6.2
Java Version: 1.7.0_45, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 88282848 bytes (84 MB) / 174587904 bytes (166 MB) up to 829423616 bytes (791 MB)
JVM Flags: 0 total;
AABB Pool Size: 7399 (414344 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
Profiler Position: N/A (disabled)
Vec3 Pool Size: 947 (53032 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Player Count: 1 / 10; [mp['FlossyDSM'/527, l='', x=-4155.70, y=93.00, z=3855.04]]
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)