Ok so i made a mod with with forge it works perfectly in ssp but when i try it in smp i get this error:

 

[sEVERE] Encountered an unexpected exception LoaderException
cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: Obsidian.common.clientProxyObsidian
at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:68)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:417)
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:69)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
at com.google.common.eventbus.EventBus.post(EventBus.java:268)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:140)
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:69)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
at com.google.common.eventbus.EventBus.post(EventBus.java:268)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:83)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:478)
at cpw.mods.fml.server.FMLServerHandler.beginServerLoading(FMLServerHandler.java:80)
at cpw.mods.fml.common.FMLCommonHandler.onServerStart(FMLCommonHandler.java:339)
at hg.c(DedicatedServer.java:49)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:454)
at fp.run(SourceFile:818)
Caused by: java.lang.ClassNotFoundException: Obsidian.common.clientProxyObsidian
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:126)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:57)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:51)
... 27 more
Caused by: java.lang.NoClassDefFoundError: Obsidian/common/clientProxyObsidian (wrong name: Obsidian/client/clientProxyObsidian)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:120)
... 33 more

Why is your "clientProxyObsidian" inside Common?

Shouldn't it be in Client?

Bcs i was trying

 

and if it is in the client folder i get this error

 

[sEVERE] Encountered an unexpected exception LoaderException
cpw.mods.fml.common.LoaderException: java.lang.ClassNotFoundException: Obsidian.common.clientProxyObsidian
at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:68)
at cpw.mods.fml.common.FMLModContainer.constructMod(FMLModContainer.java:417)
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:69)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
at com.google.common.eventbus.EventBus.post(EventBus.java:268)
at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:140)
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:69)
at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:317)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:300)
at com.google.common.eventbus.EventBus.post(EventBus.java:268)
at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:83)
at cpw.mods.fml.common.Loader.loadMods(Loader.java:478)
at cpw.mods.fml.server.FMLServerHandler.beginServerLoading(FMLServerHandler.java:80)
at cpw.mods.fml.common.FMLCommonHandler.onServerStart(FMLCommonHandler.java:339)
at hg.c(DedicatedServer.java:49)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:454)
at fp.run(SourceFile:818)
Caused by: java.lang.ClassNotFoundException: Obsidian.common.clientProxyObsidian
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:126)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at cpw.mods.fml.common.ModClassLoader.loadClass(ModClassLoader.java:57)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at cpw.mods.fml.common.ProxyInjector.inject(ProxyInjector.java:51)
... 27 more
Caused by: java.lang.NullPointerException
at org.objectweb.asm.ClassReader.<init>(Unknown Source)
at net.minecraftforge.transformers.EventTransformer.transform(EventTransformer.java:29)
at cpw.mods.fml.relauncher.RelaunchClassLoader.runTransformers(RelaunchClassLoader.java:163)
at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:119)
... 33 more

 

 

Did you remember to change the reference to your proxy in your @Mod class from

Obsidian.common.clientProxyObsidian

to

Obsidian.client.clientProxyObsidian

(or whatever your client proxy's location is)?

Do you mean this?

 

	@SidedProxy(clientSide="Obsidian.client.clientProxyObsidian",serverSide="Obsidian.common.clientProxyObsidian")
public static commonProxyObsidian proxy;

On the server side, you're trying to load a client proxy from the common package.

 

The point of Proxies is that you use different ones for the server and client, and you are trying to use the same...

Ok, thanks and how do i fix this? 

Follow this Tutorial: http://www.minecraftforge.net/wiki/Category:Generic_Mod

 

More specifically, this part of the tut: http://www.minecraftforge.net/wiki/Tutorials/Basic_Modding

 

The generic mod explains the basics of modding very thoroughly in a comprehensive manner.

Basic Modding Tutorial explains all you need to know about proxies.

Thank you very much, i'll let u know if its fixed!

Ok, so i got it to work but i had to delete a lot of lines in my mod like LanguageRegistry.addName... so i can only use the mod on a server and not in ssp is it possible to make it universal?

You should not have to delete anything. Did you have that code inside of your proxies? If so then don't, it is supposed to go in your main file where you had 

@SidedProxy(clientSide="Obsidian.client.clientProxyObsidian",serverSide="Obsidian.common.clientProxyObsidian")

public static commonProxyObsidian proxy;

 

You only put client specific and server specific code in those files, and that does not mean all of your mod information. It should be practically empty other than whats necessary. LamguageRegistry.addName should be under the init section of the main file