If you want help, just ask in the "Discuss" section and I'll see if I can fix that problem. BUT I may not fix your problem if it involves coding, because I'm not good with coding. So please do not expect the best of help from me.
Installing a modpack using the Technic Launcher is easy. If you don't already have the launcher downloaded, visit our download page to get the latest version.
Type in the modpack name (Molten Metals) or paste the following url into the search box.
Finally, click Install at the bottom right of the launcher after you select Molten Metals from the list on the left. The launcher will handle everything else!