We have the same error and have tried to narrow it down.
Being a very new user to IC2, we do not have hardly anything running with it yet.
3 Mercs, 2 Base generators, 2 electric furnaces, 1 batbox.
While my session was ok, my wife's kept crashing with this error.
I removed all fuel from the generators, and waited until the machine fully shutdown.
Once fully off, my wife's session worked just fine for a couple of hours.
Then She restarted the machine and logged off... Now neither of us can get back in the game.
From the other posts, sounds like a power generation issue.
Hope this helps!!