I created a mod for 1.6.2 and zipped it like this (in eclipse the mod worked fine):

RPG-HUD 1.1.zip

 

included are the assets ("assets/rpghud/damage.png" and "assets/rpghud/interface.png"), the src files: "minecraft/net/spellcraftgaming/rpghud/GuiIngameRPG"  and "minecraft/net/spellcraftgaming/rpghud/RPGHud".

 

Here is the error code:

---- Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!

Time: 17.07.13 00:19
Description: There was a severe problem during mod loading that has caused the game to fail

cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: net.spellcraftgaming.rpghud.RPGHud
at cpw.mods.fml.common.LoadController.transition(LoadController.java:149)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:520)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:182)
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(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:57)
at net.minecraft.launchwrapper.Launch.main(Launch.java:18)
Caused by: java.lang.ClassNotFoundException: net.spellcraftgaming.rpghud.RPGHud
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:58)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:457)
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 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:194)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:174)
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 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:105)
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: Windows 7 (x86) version 6.1
Java Version: 1.7.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
Memory: 10043144 bytes (9 MB) / 79413248 bytes (75 MB) up to 518979584 bytes (494 MB)
JVM Flags: 1 total; -Xmx512M
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 v6.2.30.794 Minecraft Forge 9.10.0.794 4 mods loaded, 4 mods active
mcp{8.04} [Minecraft Coder Pack] (minecraft.jar) Unloaded->Constructed
FML{6.2.30.794} [Forge Mod Loader] (coremods) Unloaded->Constructed
Forge{9.10.0.794} [Minecraft Forge] (coremods) Unloaded->Constructed
rpghud{1.1} [rpghud] (RPG-HUD 1.1.zip) Unloaded->Errored

 

I don't know why it does not work properly...

isn't your spellcraftgaming package directory supposed to be in the minecraft directory, not in the net package?

 

Just looks like a namespace thing.