I had the exact same problem and after seeing this I did some more research outside of the forum and found out that an easy fix is to click the cog wheel at the top right of the screen and allocate 2GB of memory and click the box to allow perm gem size, make sure you save, then it will ask you to relaunch the technic launcher, say yes, wait a few moments then open the pack. an additional note, I only made an account to help you, I hope you feel the appreciation.