I have the same problem Dekker had.
Forge Mod Loader has found a problem with your minecraft installation
A mod sorting cycle was detected and loading cannot continue
It mentions about the Buildcraft silicon, buildcraft factory, bc energy, bc core...
It happened right after I updated my GT6 version to the newest version.
I did check other mods' updates, and I am playing my customized mod pack in Curse(FTB).
It works perfectly fine if I remove gregtech and play.
I can't understand Gorilla's reply because of language, so....
Edit: ultrasn0w's ForgeMultipart file made me happy again
Thank you those who try to help me (I'm sorry that I didn't really see any other replys except Gorllia's)