Board Thread:Wiki/Forum Technical Support/@comment-93.82.62.210-20151208164612/@comment-26172435-20151208165746

Run your minecraft client with version 1.7.10, if you haven't run that version before with your current installed client. Just once in single player is enough, and then close your client.

Then install Forge, preferrably version 10.13.2.1291, from this page: http://files.minecraftforge.net/maven/net/minecraftforge/forge/index_1.7.10.html. Place the installer you need in your minecraft folder and make it run. It will install a minecraft forge version in your \.minecraft\versions folder named '1.7.10-Forge10.13.2.1291'.

Finally you can start your minecraft client again and create a new profile using version 'release 1.7.10-Forge10.13.2.1291'. Give the new profile an appropriate name like '1.7.10 Forge'. Play!

I assume you have the LOTR mod installed in your \.minecraft\mods folder.

Enjoy!