Triggering some corpse-using spells

[tml616]

I have several spells on a hero that are no-target, instant cast which use a nearby corpse to raise a minion. I would like it to function so that the closest corpse within 720 range is used and if there are none, an error message appears and the spell isn't cast (no mana used or cooldown activated). To do the second part would I have to trigger a "Stop" command when the spell begins casting, or is there another way to get a hardcoded error?

 

[cazador]

If you are making the spell with triggers the unic way to make a error menssage to appear is with triggering...

Something like two blocks of conditions. One is the correct where it meets the conditions and other where it doesn't and the message appear.