1.7.4 server crash

Server crashes pretty often. I have to restart it after this happens.

---- Minecraft Crash Report ----
// I blame Dinnerbone.

Time: 2-2-14 20:03
Description: Ticking entity

java.lang.OutOfMemoryError: Java heap space
	at go.a(SourceFile:191)
	at gq.<init>(SourceFile:44)
	at mp.h(SourceFile:186)
	at afs.a(SourceFile:1368)
	at mm.a(SourceFile:480)
	at afs.g(SourceFile:1346)
	at afs.h(SourceFile:1253)
	at mm.h(SourceFile:365)
	at net.minecraft.server.MinecraftServer.u(SourceFile:510)
	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 go.a(SourceFile:191)
	at gq.<init>(SourceFile:44)
	at mp.h(SourceFile:186)
	at afs.a(SourceFile:1368)
	at mm.a(SourceFile:480)
	at afs.g(SourceFile:1346)

-- Entity being ticked --
Details:
	Entity Type: null (mp)
	Entity ID: 67
	Entity Name: NexusTimo
	Entity's Exact location: -54004,40, 62,17, -48822,01
	Entity's Block location: World: (-54005,62,-48823), Chunk: (at 11,3,9 in -3376,-3052; contains blocks -54016,0,-48832 to -54001,255,-48817), Region: (-106,-96; contains chunks -3392,-3072 to -3361,-3041, blocks -54272,0,-49152 to -53761,255,-48641)
	Entity's Momentum: 0,00, 0,17, 0,00
Stacktrace:
	at afs.h(SourceFile:1253)
	at mm.h(SourceFile:365)

-- Affected level --
Details:
	Level name: world
	All players: 3 total; [mp['NexusTimo'/67, l='world', x=-54004,40, y=62,17, z=-48822,01], mp['Burngold'/1176, l='world', x=39739,46, y=33,00, z=40099,35], mp['zzephy'/50228, l='world', x=40160,75, y=72,02, z=40072,48]]
	Chunk stats: ServerChunkCache: 3254 Drop: 0
	Level seed: -1306361481829046829
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (252,64,232), Chunk: (at 12,4,8 in 15,14; contains blocks 240,0,224 to 255,255,239), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 3187128 game time, 94169 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 55050 (now: false), thunder time: 55766 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.u(SourceFile:510)
	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 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: 34232 bytes (0 MB) / 259522560 bytes (247 MB) up to 259522560 bytes (247 MB)
	JVM Flags: 0 total; 
	AABB Pool Size: 18335 (1026760 bytes; 0 MB) allocated, 632 (35392 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 4249 (237944 bytes; 0 MB) allocated, 136 (7616 bytes; 0 MB) used
	Player Count: 3 / 20; [mp['NexusTimo'/67, l='world', x=-54004,40, y=62,17, z=-48822,01], mp['Burngold'/1176, l='world', x=39739,46, y=33,00, z=40099,35], mp['zzephy'/50228, l='world', x=40160,75, y=72,02, z=40072,48]]
	Is Modded: Unknown (can't tell)
	Type: Dedicated Server (map_server.txt)