Minecraft Forums

First I would like to thank in advance everyone that can help.

My son loves minecraft and is running 1.5.2 and have installed Forge 7.8.0.684 on a Macbook Pro. Minecraft runs properly with the install of Forge, however when I place a mod into the mods folder minecraft crashes. When I remove the mod from the mods folder everything runs fine again. I have tried to install the following mods Mutant Creatures and Statues, neither works when placed in the appropriate folder. Here is the crash report:

---- Minecraft Crash Report ----
// Oops.

Time: 5/30/13 6:36 PM
Description: Failed to start game

cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: mods.MutantCreatures.MutantCreatures
at cpw.mods.fml.common.LoadController.transition(LoadController.java:142)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:513)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:160)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:410)
at net.minecraft.client.MinecraftAppletImpl.func_71384_a(SourceFile:56)
at net.minecraft.client.Minecraft.run(Minecraft.java:732)
at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.ClassNotFoundException: mods.MutantCreatures.MutantCreatures
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:238)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:56)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:425)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:165)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
at com.google.common.eventbus.EventBus.post(EventBus.java:267)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:98)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:503)
... 5 more
Caused by: java.lang.NullPointerException
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:227)
... 32 more


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

-- System Details --
Details:
Minecraft Version: 1.5.2
Operating System: Mac OS X (x86_64) version 10.7.5
Java Version: 1.6.0_45, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 2081895840 bytes (1985 MB) / 2145320960 bytes (2045 MB) up to 6287130624 bytes (5995 MB)
JVM Flags: 3 total; -Xbootclasspath/a:/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/Resources/LauncherSupport.jar -Xms2048M -Xmx6000M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Suspicious classes: FML and Forge are installed
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP v7.51 FML v5.2.2.684 Minecraft Forge 7.8.0.684 4 mods loaded, 4 mods active
mcp{7.44} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML{5.2.2.684} [Forge Mod Loader] (coremods) Unloaded->Constructed
Forge{7.8.0.684} [Minecraft Forge] (coremods) Unloaded->Constructed
MutantCreatures{1.3.4} [Mutant Creatures] (MutantCreatures.zip) Unloaded->Errored
LWJGL: 2.4.2
OpenGL: NVIDIA GeForce 8600M GT OpenGL Engine GL version 2.1 NVIDIA-7.32.12, NVIDIA Corporation
Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Texture Pack: Default
Profiler Position: N/A (disabled)
Vec3 Pool Size: ~~ERROR~~ NullPointerException: null

I have the same problem. First remove the mods from the mods folder. Then I would look up on YouTube how to install 7-Zip or any Archiving program. It may say it could harm your computer but just ignore that. After you have done that right click on the mod. It should appear on the bar 7-Zip or WinRar. Then hover over it and click Open Archive. Now I've never done this on a Mac, but on Windows you go to C:/User/UsersNameHere-main.-PC.XXX/AppData/Roaming/.minecraft/bin. If you don't have that then try and find your .minecraft folder. Then open that and go to your bin. In the bin there should be a jar file called minecraft. Right click on minecraft and hover over 7-Zip or WinRar and click Open Archive. Now select all of the files from your mod's zip file and drag them into your minecraft zip file. Make sure NOT to drag them into a folder. Try to drag it in an open, white area. Repeat this with both mods and it should work.

Enderroommate

Thanks. Although I am not using a windows computer, I understand what you are saying. I have put both zip files and unziped files of the mod into the mods folder and neither work. I get the same error report.