I downloaded the new IC2 v 1.23, put the .jar in the mod folder and removed the old version and now MC crashes on start up.
The only change was swapping out the IC2 .jar files from 1.15 to 1.23 and before that it worked great.
Here is the crash log
Mods loaded: 7
ModLoader Beta 1.8.1
mod_BuildCraftCore 2.2.2
mod_BuildCraftBuilders 2.2.2
mod_BuildCraftEnergy 2.2.2
mod_BuildCraftFactory 2.2.2
mod_BuildCraftTransport 2.2.2
mod_EE 1.8.1
Minecraft has crashed!
----------------------
Minecraft has stopped running because it encountered a problem.
If you wish to report this, please copy this entire text and email it to support@mojang.com.
Please include a description of what you did when the error occured.
--- BEGIN ERROR REPORT e872e214 --------
Generated 10/29/11 5:42 PM
Minecraft: Minecraft Beta 1.8.1
OS: Windows 7 (amd64) version 6.1
Java: 1.6.0_27, Sun Microsystems Inc.
VM: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Sun Microsystems Inc.
LWJGL: 2.4.2
OpenGL: GeForce 9400M/PCI/SSE2 version 3.3.0, NVIDIA Corporation
java.lang.NoClassDefFoundError: forge/IOreHandler
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.privateGetPublicFields(Unknown Source)
at java.lang.Class.getFields(Unknown Source)
at ModLoader.setupProperties(ModLoader.java:1583)
at ModLoader.addMod(ModLoader.java:274)
at ModLoader.readFromModFolder(ModLoader.java:1179)
at ModLoader.init(ModLoader.java:824)
at ModLoader.AddAllRenderers(ModLoader.java:186)
at aam.(aam.java:61)
at aam.(aam.java:10)
at net.minecraft.client.Minecraft.a(SourceFile:259)
at net.minecraft.client.Minecraft.run(SourceFile:629)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: forge.IOreHandler
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 14 more
--- END ERROR REPORT 181176ca ----------
</init>