Packet is missing a mapping?

I get this error, which makes no sense because i have another class which is almost identical extending the DemoPacket class.

---- Minecraft Crash Report ----

// I blame Dinnerbone.

Time: 11/24/13 9:24 PM

Description: Updating screen events

java.lang.RuntimeException: Packet PurchasePacket is missing a mapping!

at packets.DemoPacket.getPacketId(DemoPacket.java:62)

at packets.DemoPacket.makePacket(DemoPacket.java:68)

at packets.ShopGui.actionPerformed(ShopGui.java:116)

at net.minecraft.client.gui.GuiScreen.mouseClicked(GuiScreen.java:120)

at net.minecraft.client.gui.GuiScreen.handleMouseInput(GuiScreen.java:208)

at net.minecraft.client.gui.GuiScreen.handleInput(GuiScreen.java:176)

at net.minecraft.client.Minecraft.runTick(Minecraft.java:1566)

at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:910)

at net.minecraft.client.Minecraft.run(Minecraft.java:838)

at net.minecraft.client.main.Main.main(Main.java:93)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)

at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

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

---------------------------------------------------------------------------------------

-- Head --

Stacktrace:

at packets.DemoPacket.getPacketId(DemoPacket.java:62)

at packets.DemoPacket.makePacket(DemoPacket.java:68)

at packets.ShopGui.actionPerformed(ShopGui.java:116)

at net.minecraft.client.gui.GuiScreen.mouseClicked(GuiScreen.java:120)

at net.minecraft.client.gui.GuiScreen.handleMouseInput(GuiScreen.java:208)

at net.minecraft.client.gui.GuiScreen.handleInput(GuiScreen.java:176)

-- Affected screen --

Details:

Screen name: packets.ShopGui

-- Affected level --

Details:

Level name: MpServer

All players: 1 total; [EntityClientPlayerMP['Player633'/5, l='MpServer', x=836.30, y=5.62, z=2165.71]]

Chunk stats: MultiplayerChunkCache: 441

Level seed: 0

Level generator: ID 01 - flat, ver 0. Features enabled: false

Level generator options:

Level spawn location: World: (1350,4,971), Chunk: (at 6,0,11 in 84,60; contains blocks 1344,0,960 to 1359,255,975), Region: (2,1; contains chunks 64,32 to 95,63, blocks 1024,0,512 to 1535,255,1023)

Level time: 20729 game time, 20729 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: 44 total; [EntityPixelmon['Nidorina'/64, l='MpServer', x=927.56, y=4.00, z=2188.72], EntityClientPlayerMP['Player633'/5, l='MpServer', x=836.30, y=5.62, z=2165.71], EntityPixelmon['Farfetchd'/14, l='MpServer', x=744.19, y=4.00, z=2170.31], EntityPixelmon['Farfetchd'/16, l='MpServer', x=738.63, y=4.00, z=2178.78], EntityPixelmon['Miltank'/19, l='MpServer', x=752.84, y=4.00, z=2138.68], EntityPixelmon['Mareep'/18, l='MpServer', x=759.66, y=4.00, z=2080.84], EntityPixelmon['Fearow'/21, l='MpServer', x=762.16, y=4.00, z=2149.44], EntityPixelmon['Miltank'/20, l='MpServer', x=752.81, y=4.00, z=2140.62], EntityPixelmon['Rattata'/23, l='MpServer', x=781.78, y=4.00, z=2129.63], EntityTrainer['entity.pixelmon.Trainer.name'/25, l='MpServer', x=780.38, y=4.00, z=2243.47], EntityPixelmon['Nidoranmale'/27, l='MpServer', x=808.97, y=4.00, z=2107.72], EntityPixelmon['Snorlax'/26, l='MpServer', x=784.81, y=4.00, z=2079.31], EntityPixelmon['Electrode'/29, l='MpServer', x=787.19, y=4.00, z=2183.16], EntityTrainer['entity.pixelmon.Trainer.name'/28, l='MpServer', x=785.50, y=4.00, z=2163.00], EntityTrainer['entity.pixelmon.Trainer.name'/31, l='MpServer', x=811.25, y=4.00, z=2077.38], EntityPixelmon['Mareep'/34, l='MpServer', x=801.09, y=4.00, z=2206.81], EntityPixelmon['Girafarig'/35, l='MpServer', x=805.44, y=4.00, z=2202.50], EntityTrainer['entity.pixelmon.Trainer.name'/32, l='MpServer', x=811.03, y=4.00, z=2161.44], EntityItem['item.tile.cloth.white'/33, l='MpServer', x=812.75, y=4.13, z=2190.16], EntityPixelmon['Vulpix'/39, l='MpServer', x=828.19, y=4.00, z=2140.72], EntityItem['item.item.leather'/36, l='MpServer', x=814.09, y=4.13, z=2211.66], EntityPixelmon['Nidoranfemale'/37, l='MpServer', x=802.69, y=4.00, z=2257.78], EntityPixelmon['Mareep'/42, l='MpServer', x=821.44, y=4.00, z=2179.31], EntityPixelmon['Persian'/43, l='MpServer', x=818.31, y=4.00, z=2214.75], EntityPixelmon['Rattata'/40, l='MpServer', x=823.72, y=4.00, z=2140.81], EntityPixelmon['Mareep'/41, l='MpServer', x=824.88, y=4.00, z=2189.81], EntityTrainer['entity.pixelmon.Trainer.name'/46, l='MpServer', x=839.50, y=4.00, z=2109.47], EntityPixelmon['Arbok'/47, l='MpServer', x=841.00, y=4.00, z=2141.88], EntityPixelmon['Nidorina'/51, l='MpServer', x=853.50, y=4.00, z=2178.75], EntityItem['item.item.feather'/50, l='MpServer', x=858.53, y=4.13, z=2187.22], EntityPixelmon['Spearow'/49, l='MpServer', x=863.19, y=4.00, z=2150.66], EntityPixelmon['Rhyhorn'/48, l='MpServer', x=839.93, y=4.00, z=2144.14], EntityPixelmon['Tauros'/55, l='MpServer', x=866.38, y=4.00, z=2253.66], EntityPixelmon['Meowth'/54, l='MpServer', x=872.50, y=4.00, z=2144.50], EntityItem['item.item.goldNugget'/53, l='MpServer', x=878.06, y=4.13, z=2141.78], EntityPixelmon['Pidgeotto'/52, l='MpServer', x=868.97, y=4.00, z=2087.53], EntityPixelmon['Ekans'/59, l='MpServer', x=901.10, y=4.00, z=2085.71], EntityPixelmon['Meowth'/58, l='MpServer', x=881.66, y=4.00, z=2134.63], EntityPixelmon['Rattata'/57, l='MpServer', x=895.25, y=4.00, z=2143.13], EntityPixelmon['Girafarig'/56, l='MpServer', x=891.56, y=4.00, z=2092.59], EntityPixelmon['Nidoranfemale'/63, l='MpServer', x=916.53, y=4.00, z=2145.81], EntityPixelmon['Nidoranfemale'/62, l='MpServer', x=917.47, y=4.00, z=2100.69], EntityPixelmon['Arbok'/61, l='MpServer', x=896.63, y=4.00, z=2216.13], EntityPixelmon['Arbok'/60, l='MpServer', x=910.94, y=4.00, z=2129.50]]

Retry entities: 0 total; []

Server brand: fml,forge

Server type: Integrated singleplayer server

Stacktrace:

at net.minecraft.client.multiplayer.WorldClient.addWorldInfoToCrashReport(WorldClient.java:440)

at net.minecraft.client.Minecraft.addGraphicsAndWorldToCrashReport(Minecraft.java:2312)

at net.minecraft.client.Minecraft.run(Minecraft.java:856)

at net.minecraft.client.main.Main.main(Main.java:93)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)

at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

-- System Details --

Details:

Minecraft Version: 1.6.4

Operating System: Windows 7 (x86) version 6.1

Java Version: 1.7.0_40, Oracle Corporation

Java VM Version: Java HotSpot Client VM (mixed mode), Oracle Corporation

Memory: 517015056 bytes (493 MB) / 1037959168 bytes (989 MB) up to 1037959168 bytes (989 MB)

JVM Flags: 3 total; -Xincgc -Xmx1024M -Xms1024M

AABB Pool Size: 5955 (333480 bytes; 0 MB) allocated, 2 (112 bytes; 0 MB) used

Suspicious classes: FML and Forge are installed

IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0

FML: MCP v8.11 FML v6.4.37.941 Minecraft Forge 9.11.1.941 7 mods loaded, 7 mods active

mcp{8.09} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

FML{6.4.37.941} [Forge Mod Loader] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

Forge{9.11.1.941} [Minecraft Forge] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

pokemart{1.0.1} [pokemart] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

pixelmon{2.5.2} [Pixelmon] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

PokeMart{1.0.1} [PokeMart] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

superdatabasechecker{1.0.0} [super Database Checker] (bin) Unloaded->Constructed->Pre-initialized->Initialized->Post-initialized->Available->Available->Available->Available

Launched Version: 1.6

LWJGL: 2.9.0

OpenGL: Intel® HD Graphics Family GL version 3.1.0 - Build 8.15.10.2476, Intel

Is Modded: Definitely; Client brand changed to 'fml,forge'

Type: Client (map_client.txt)

Resource Pack: Default

Current Language: Español (Argentina)

Profiler Position: N/A (disabled)

Vec3 Pool Size: 379 (21224 bytes; 0 MB) allocated, 15 (840 bytes; 0 MB) used