Bug with my personalizzed launcher!

[lorizz]

Hey guys, I'm 13 and I'm italian.

I know that I didn't presented yet but I got a problem and I only have 2 days for this freaking launcher!

In a custom launcher, for download the resources, coremds ecc. folders, I need to modify this bit of code:

public static File getMinecraftDir()
    {
    	if(minecraftDir == null) {
    		
    	minecraftDir = getAppDir("universecraft"); //here I changed "minecraft" with my custom name directory "universecraft"
            
        }

        return minecraftDir;
    }

 

BUT!:

2013-03-06 20:15:48 [iNFO] [ForgeModLoader] Searching C:\Users\Documenti\Desktop\Ale\Minecraft\Script\MCPforge\jars\mods for mods

If I change "if(minecraftDir == null)" to "if(minecraftDir != null)"

and it change the directory to:

2013-03-06 20:17:35 [iNFO] [ForgeModLoader] Searching C:\Users\Documenti\AppData\Roaming\.universecraft\mods for mods

 

But it give me this error:

 

2013-03-06 20:18:10 [iNFO] [sTDERR] Exception in thread "Minecraft main thread" java.lang.NoSuchFieldError: manager
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at mutantcreatures.MCHandler.addSound(MCHandler.java:61)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at mutantcreatures.MCHandler.onSound(MCHandler.java:33)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraftforge.event.ASMEventHandler_4_MCHandler_onSound_SoundLoadEvent.invoke(.dynamic)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraftforge.event.ASMEventHandler.invoke(ASMEventHandler.java:35)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraftforge.event.EventBus.post(EventBus.java:103)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraft.client.audio.SoundManager.loadSoundSettings(SoundManager.java:80)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraft.client.Minecraft.startGame(Minecraft.java:442)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraft.client.MinecraftAppletImpl.startGame(MinecraftAppletImpl.java:44)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at net.minecraft.client.Minecraft.run(Minecraft.java:745)
2013-03-06 20:18:10 [iNFO] [sTDERR] 	at java.lang.Thread.run(Unknown Source)

 

Any help?