Minecraft crashes when trying to place a Mob Spawner

I gave myself a monster spawner with /give trueboy012 52 1. When I tried to place the spawner Minecraft crashed. The client is modded with 5 mods.

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 12/23/12 11:32 AM
Description: Unexpected error

java.lang.NullPointerException
	at TMIItemSpawner.a(TMIItemSpawner.java:42)
	at ur.a(SourceFile:88)
	at ayo.a(SourceFile:240)
	at net.minecraft.client.Minecraft.c(SourceFile:982)
	at net.minecraft.client.Minecraft.l(SourceFile:1296)
	at net.minecraft.client.Minecraft.J(SourceFile:582)
	at net.minecraft.client.Minecraft.run(SourceFile:534)
	at java.lang.Thread.run(Unknown Source)


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

-- Head --
Stacktrace:
	at TMIItemSpawner.a(TMIItemSpawner.java:42)
	at ur.a(SourceFile:88)
	at ayo.a(SourceFile:240)
	at net.minecraft.client.Minecraft.c(SourceFile:982)

-- Affected level --
Details:
	Level name: MpServer
	All players: 1 total; [ays['trueboy012'/3568, l='MpServer', x=-228.86, y=57.62, z=-567.47]]
	Chunk stats: MultiplayerChunkCache: 441
	Level seed: 0
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 
	Level spawn location: World: (-203,4,-567), Chunk: (at 5,0,9 in -13,-36; contains blocks -208,0,-576 to -193,255,-561), Region: (-1,-2; contains chunks -32,-64 to -1,-33, blocks -512,0,-1024 to -1,255,-513)
	Level time: 750462 game time, 98285 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: creative (ID 1). Hardcore: false. Cheats: false
	Forced entities: 3 total; [pd['Pig'/3541, l='MpServer', x=-223.84, y=56.00, z=-495.75], ays['trueboy012'/3568, l='MpServer', x=-228.86, y=57.62, z=-567.47], pd['Pig'/3536, l='MpServer', x=-269.99, y=56.00, z=-627.91]]
	Retry entities: 0 total; []
Stacktrace:
	at ayp.a(SourceFile:281)
	at net.minecraft.client.Minecraft.b(SourceFile:1871)
	at net.minecraft.client.Minecraft.run(SourceFile:548)
	at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
	Minecraft Version: 1.4.6
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_02, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1719973984 bytes (1640 MB) / 2058027008 bytes (1962 MB) up to 2058027008 bytes (1962 MB)
	JVM Flags: 2 total; -Xmx2048m -Xms2048m
	AABB Pool Size: 10624 (594944 bytes; 0 MB) allocated, 3 (168 bytes; 0 MB) used
	Suspicious classes: ModLoader, EntityRendererProxy, ModTextureStatic, ...reifnsk.minimap.ReiMinimap, GuiScreenInterface, GuiOptionScreen, ...
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	ModLoader: Mods loaded: 4
ModLoader 1.4.6
mod_TooManyItems 1.4.6 2012-12-17
mod_ReiMinimap v3.2_05 [1.4.6]
mod_RecipeBook 1.4.6

	LWJGL: 2.4.2
	OpenGL: AMD M880G with ATI Mobility Radeon HD 4250        GL version 3.3.10179 Compatibility Profile Context, ATI Technologies Inc.
	Is Modded: Very likely; Jar signature invalidated
	Type: Client (map_client.txt)
	Texture Pack: Default
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 104 (5824 bytes; 0 MB) allocated, 20 (1120 bytes; 0 MB) used