Return of Reckoning

Hello, I'm trying to install some addons and I'm having troubles.
For example, the addon Buffhead won't pop it's configuration window. It is well unziped into the Addons folder, and it is also working great in game.
But I can't configure anything, when I type /buffhead or even /command, there's a "unknown command" message in the chat.
Can someone help me with this ?

Do you have the addon Libslash installed?

Is it like the main Addon who make all the others works depending of him ? Then no, it's not installed

Okay. That's working perfectly. Thank you sir

Bout 90% of addons uses libslash for /slash commands