So i've ´been having this problem for a few days now and its realy annoying because all my advanced mashinery is getting cooled off due to this. Basically what is happening is that when i log in the optic fibre cables( and possibly other types as well) dont transmit the power. The power source( MFE) is full, but my mashines just dont get any power. Sometimes few of them get the power but the rest(they're in a row) dont. Breaking and replacing the cable doesnt help. The only way to fix this is to exit the world and enter it again.
I have the newest version of advanced mashines and IC2 as well as forge and modloader.