This mod has been removed due to online bugs: in some situations, when using this mod you cannot damage other players, so you probably don't want that!
If you are going to play online, it is best to disable this mod before starting the game by putting a "-" at the beginning of the name of the folder in which you install the mod (eg \Mods\NationsAndSquadrons would become \Mods\-NationsAndSquadrons).
I would guess that using it offline is not a problem.