I was going to post this under the more than 256 blocks post but you quickly dismissed and locked it.
I have not tried with that mod but I did with Robintons4096, IC2 will not work with it.
I did a completely fresh install. Only put ML, MLMP, Forge, the proper ID resolver mod for the extended and Robintons in the jar.
Dropped IC2 in mods folder. Immediately crashes. I have every other industrial style mod installed and they all worked fine with it.