I use Molinari with Arkinventory, French client (frFR). Tried to use it alone too, but have the same bug. In order to have Molinari working, i need to reload UI. Without doing this, it's as if Molinari was not loaded.

What version are you using?

I'm using version 30300.3-Beta

edit : just seen that it wasn't the latest one, as I use Curse client to update my addons, it seems that Molinari was not updated at Curse. Will try the version i just downloaded in here.