Ok, so im making this mod and when I run it in eclipse everything works fine, no crashing no errors, however when i recompile and reobfuscate and run it for a test run everything goes wrong. I think it is how I have the files, as I almost am never the one recompiling the mod. Anyways heres my crash report and if you want me to upload my actual mod so you can see how I configured my files in it I can.

 

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 7/14/13 9:43 AM
Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: sandwichmod.Sandwich
at cpw.mods.fml.common.LoadController.transition(LoadController.java:148)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:520)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:172)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:470)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:796)
at net.minecraft.client.main.Main.main(SourceFile:101)
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 net.minecraft.launchwrapper.Launch.launch(Launch.java:57)
at net.minecraft.launchwrapper.Launch.main(Launch.java:18)
Caused by: java.lang.ClassNotFoundException: sandwichmod.Sandwich
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)
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:58)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:457)
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:313)
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.sendEventToModContainer(LoadController.java:193)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:173)
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:313)
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:104)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:510)
... 10 more
Caused by: java.lang.NullPointerException
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:171)
... 38 more


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

-- System Details --
Details:
Minecraft Version: 1.6.2
Operating System: Mac OS X (x86_64) version 10.8.4
Java Version: 1.6.0_51, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 30084000 bytes (28 MB) / 103530496 bytes (98 MB) up to 1065025536 bytes (1015 MB)
JVM Flags: 1 total; -Xmx1G
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 v8.04 FML v6.2.19.789 Minecraft Forge 9.10.0.789 4 mods loaded, 4 mods active
mcp{8.04} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML{6.2.19.789} [Forge Mod Loader] (coremods) Unloaded->Constructed
Forge{9.10.0.789} [Minecraft Forge] (coremods) Unloaded->Constructed
sandwich{0.0.1} [sandwich] (SandwichMod V1.0) Unloaded->Errored

 

I figured it out, turns out it wasn't decompiling correctly due to a mistake I made. Please close or delete this thread.