I didn't see this until much later. As far as I know, the server was idle when this happened.

---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 10/14/13 5:41 PM
Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
at ml.c(SourceFile:130)
at net.minecraft.server.MinecraftServer.u(SourceFile:529)
at le.u(SourceFile:259)
at net.minecraft.server.MinecraftServer.t(SourceFile:441)
at net.minecraft.server.MinecraftServer.run(SourceFile:358)
at kt.run(SourceFile:617)

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

– System Details –
Details:
Minecraft Version: 13w41b
Operating System: Linux (amd64) version 3.8.0-19-generic
Java Version: 1.7.0_25, Oracle Corporation
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 793069152 bytes (756 MB) / 843186176 bytes (804 MB) up to 1849229312 bytes (1763 MB)
JVM Flags: 0 total;
AABB Pool Size: 0 (0 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: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Player Count: 0 / 5; []
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)