Help with JASS (Error: expected a name)

Alright hello there

I recently put Lord Vexorian's caster system into my map to use it with spells, the map itself is for me and a friend. Now when using the function DamageUnitsInAOE i get a compile error saying expected a name, but I don't get what it means. Can anyone help me?

Hold up I changed the function to DamageUnitsInAOELoc and got it to work perfectly, but to make it work I had to add a constant function at the top of the map to deal the damage and to make it work.

Now I'm just curious, does the DamageUnitsInAOELoc function require you to state the damage as a constant, and does anything else need to be a constant?