[Trigger] rain with damage ability

[Rubber]

I have this trigger, this ability create a cloud(is a ability units->I transform in hero ability) and ut's ok with spell animation, but the damage don't run why?

• Inizializzazione partita Assalto
  • Eventi
    • UnitÃ* - A unit Avvia l'effetto di un'abilitÃ*
  • Condizioni
    • (Ability being cast) Uguale a nuvola
  • Azioni
    • UnitÃ* - Pausa (Target unit of ability being cast)
    • Effetto speciale - Create a special effect attached to the hand, left, right of (Casting unit) using Doodads\Ruins\Water\BubbleGeyser\BubbleGeyser.mdl
    • Audio - Play LightningBolt1 <gen>
    • UnitÃ* - Cause target_unit[(Player number of (Owner of (Target unit of ability being cast)))] to damage caster_unit[(Player number of (Owner of (Casting unit)))], dealing 100.00 damage of attack type Incantesimi and damage type Fulmine
    • Wait 5.00 seconds
    • UnitÃ* - Riprendi (Target unit of ability being cast)
    • Effetto speciale - Destroy (Last created special effect)

 

[Squiggy]

Uh - you neither declared that target_unit[(Player number of (Owner of (Target unit of ability being cast))) nor caster_unit[(Player number of (Owner of (Casting unit)))] in that trigger and if the variables aren't declared, warcraft uses 'no unit'

 

[Rubber]

else, how i put?