Lewis Cawte

I got this error when I upgraded to 3.1.(the new one)... I worked out the problem though... When you upgraded, I assume you deleted your "mods" folder/directory... the issue was caused when I did this, but I did not delete my Tekkit.jar, and I said no to files overwriting because I didn't want to lose config, this can be fixed by deleting the Jar and re-unzipping the new release, choosing No to overwriting files.