I keep reverting to older versions to play because everytime i update IC2 it crashes with this same error.
Thanks for the help! 
I keep reverting to older versions to play because everytime i update IC2 it crashes with this same error.
Thanks for the help!
Are you sure you actually updated to the real, latest version? This was fixed a while ago.
His problem is because the IC² API updated in that version and all the mods which contains outdated API will crash.
To solve : Open all your mods zip/jar (rather than IC²) and delete all API files (of IC²) you find inside them.