I hope that solves your problem.
If not, have you tried the FTB launcher? Each mod pack you play from FTB has a separate folder with all the files necessary for all the mods making up the mod pack. Keeps everything in separate folders and keeps track of which mod needs which version of each mod pack. I've never had a problem with it. I've never had to manually install anything for a mod pack and it all just works.
I used FTb as well. Never had any problems with the mods. This is the first time this happens to a modpack.
I guess the updated forge did the trick. Playing since i wrote the last post and no freezing until now. I can even shift click items into minechem