It seems that gregtech is giving you the issue. Its most likely its compatibility with IC2. It would look into getting the newest version of gregtech here -> http://files.minecraftforge.net/maven/com/gregoriust/gregtech/gregtech_1.7.10/index.html
and/or updating your IC2 here -> http://ic2api.player.to:8080/job/IC2_experimental/lastSuccessfulBuild/artifact/build/libs/industrialcraft-2-2.2.650-experimental.jar.
Unfortunately, i dont use gregtech myself, but i hope this at least gets you started in the right direction. If you still have issues let me know and ill download all the mods myself and test it out.
