Urg, don't you just hate it when developers don't change the version number that ModLoader reads? The charging bench IC2 addon is v1.70-1, ModLoaderMP is 1.1.0 v2, and Equivalent Exchange is v1.38.
I get this error a few moments after I enter my single player world; as chunks load in front of me, it tries to load my IC2 agriculture lab, and it crashes. If it's relevant, it's that annoying crash-method where the error log blinks into and out of existience; I had to run minecraft from the command line to get the error log. 