[Support Request] Black Screen, when Minecraft Forge is installed.

Are you sure you also installed Modloader MP ?

BTW: When it still doesn´t work, force update and try again

I get the black screen, too.
If i do force update, it get the 1.9 (1.0).
I have installed the 3 mods in order (ModLoader, ModLoaderMp & minecraftforge-client), and put the mods (IC2 and BC2) in the mods folder.
Always get a black screen...
(i cannot delete META folder, it not appear to me).
I have tried with several minecraft.jar clients (supposed to be 1.8.1). I cannot get a new 100% sure clean one because the 1.9 has arrive (damn it, if i tried the same a week before...)

Sorry, i have several times to get the error log, but in a mac environment it's hard...
(i have test step by step, and i obtain the black screen as soon as i install de ModLoader, but i use the version linked in the wiki)

Ok, at least the error...

With my usual launcher (i always use this) throw me this error:

Hello!
URL: file:/Users/achiles/Library/Application%20Support/minecraft/bin/lwjgl.jar
URL: file:/Users/achiles/Library/Application%20Support/minecraft/bin/jinput.jar
URL: file:/Users/achiles/Library/Application%20Support/minecraft/bin/lwjgl_util.jar
URL: file:/Users/achiles/Library/Application%20Support/minecraft/bin/minecraft.jar
URL: file:/Users/achiles/Library/Application%20Support/minecraft/bin/macosx_natives.jar
Exception in thread "Thread-4" java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at net.minecraft.client.Minecraft.<init>(SourceFile:106)
at l.<init>(SourceFile:34)
at net.minecraft.client.MinecraftApplet.init(SourceFile:34)
at net.minecraft.Launcher.replace(Launcher.java:153)
at net.minecraft.Launcher$1.run(Launcher.java:94)

With the original, unmodified one, it throw me this:

Exception in thread "Thread-8" java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at net.minecraft.client.Minecraft.<init>(SourceFile:106)
at l.<init>(SourceFile:34)
at net.minecraft.client.MinecraftApplet.init(SourceFile:34)
at net.minecraft.Launcher.replace(Launcher.java:143)
at net.minecraft.Launcher$1.run(Launcher.java:87)

Or all the mine craft.jar i tried are wrong (or not clean) or the ModLoader.zip linked (the one all people use) are wrong.
I have pathing clients from many months (and my server, too), but i never stuck like this time.

I have advanced a bit.
Now the error is the next: