I get the same problem whenever I try to use this skill:
Usable: Only in menu
What it does: Calls a common event
Whenever I try to use it in-game, it lets me select the character, but just buzzes i.e it cannot be used.
I've tried making the skill do damage, lowering the actors HP before using it, but it just doesn't work. I've also tested making my other skills that actually do something cost 0 and be only usable in the menu, they seem to work, so why not this one?