Casting Brutal Strike

[L!p3]

Hi, I'm with a problem using Brutal Strike by Targeting.
I want to use Brutal strike when the creature is 1 sqm near, but It's casting even if it's 7 sqm away and it keep spamming until the reach the creature. That's what I did:

http://i.imgur.com/hslGb.png

Any Idea how to solve that?

Thanks.