IC2 experimental should work on most forge versions for the same version of minecraft (for example, I have forge 9.10.1.859, and amusing IC2 experimental 260).
If you downloaded IC2 from that website, it is not a legitimate website to download IC2 at. This forum has links to the Jenkins sites where you can download IC2. IC2 was updated up to 1.5.2, IC2 lf was updated to 1.6.2 (but was quite buggy), and IC2 experimental is updated to 1.6.2/4 and is the only version being updated, it is relatively bug free, and has revamped/new features over the other versions.