Bug on the server

Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 09/03/13 18:15
Description: Ticking entity

java.lang.OutOfMemoryError: Java heap space
at dv.<init>(SourceFile:62)
at jc.l_(SourceFile:153)
at zv.a(SourceFile:1336)
at iz.a(SourceFile:508)
at zv.g(SourceFile:1314)
at zv.h(SourceFile:1221)
at iz.h(SourceFile:390)
at net.minecraft.server.MinecraftServer.r(SourceFile:462)
at hz.r(SourceFile:255)
at net.minecraft.server.MinecraftServer.q(SourceFile:397)
at net.minecraft.server.MinecraftServer.run(SourceFile:331)
at gp.run(SourceFile:573)

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

– Head –
Stacktrace:
at dv.<init>(SourceFile:62)
at jc.l_(SourceFile:153)
at zv.a(SourceFile:1336)
at iz.a(SourceFile:508)
at zv.g(SourceFile:1314)

– Entity being ticked –
Details:
Entity Type: null (jc)
Entity ID: 387
Entity Name: Kerooker
Entity's Exact location: 277,57, 192,92, 5,61
Entity's Block location: World: (277,192,5), Chunk: (at 5,12,5 in 17,0; contains blocks 272,0,0 to 287,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Entity's Momentum: 0,00, -0,08, 0,00
Stacktrace:
at zv.h(SourceFile:1221)
at iz.h(SourceFile:390)

– Affected level –
Details:
Level name: Super Hostile - Inferno Mines v3.0
All players: 2 total; [jc['Rorapes'/12, l='Super Hostile - Inferno Mines v3.0', x=-143,50, y=212,00, z=-159,30], jc['Kerooker'/387, l='Super Hostile - Inferno Mines v3.0', x=277,57, y=192,92, z=5,61]]
Chunk stats: ServerChunkCache: 1509 Drop: 0
Level seed: 280886973414363531
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: World: (27,135,703), Chunk: (at 11,8,15 in 1,43; contains blocks 16,0,688 to 31,255,703), Region: (0,1; contains chunks 0,32 to 31,63, blocks 0,0,512 to 511,255,1023)
Level time: 1673290 game time, 469124 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 59389 (now: false), thunder time: 54327 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
at net.minecraft.server.MinecraftServer.r(SourceFile:462)
at hz.r(SourceFile:255)
at net.minecraft.server.MinecraftServer.q(SourceFile:397)
at net.minecraft.server.MinecraftServer.run(SourceFile:331)
at gp.run(SourceFile:573)

– System Details –
Details:
Minecraft Version: 1.5
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_11, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 1590576 bytes (1 MB) / 259522560 bytes (247 MB) up to 259522560 bytes (247 MB)
JVM Flags: 0 total;
AABB Pool Size: 4311 (241416 bytes; 0 MB) allocated, 439 (24584 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 908 (50848 bytes; 0 MB) allocated, 110 (6160 bytes; 0 MB) used
Player Count: 2 / 3; [jc['Rorapes'/12, l='Super Hostile - Inferno Mines v3.0', x=-143,50, y=212,00, z=-159,30], jc['Kerooker'/387, l='Super Hostile - Inferno Mines v3.0', x=277,57, y=192,92, z=5,61]]
Is Modded: Unknown (can't tell)
Type: Dedicated Server (map_server.txt)