I can't help you with Autohotkey, but I can say that I'm fairly certain World of Warcraft and Lord of the Rings Online do not work in the same fashion. WoW will receive keystrokes in the background, but I believe LotRO requires that the window be focused to receive input.

Most people who multibox LotRO use ISBoxer. I've also successfully boxed multiple clients on one computer with HotKeyNet. http://www.dual-boxing.com/threads/3...t-starting-out