Someone Explain Auras to me like I'm 5 LOL

Ok so -

I'm trying to activate HoI, HoT, cast on freeze and wind dancer. But for whatever reason, the skill allocation goes red on some of them when I do... I have 199 spirit...What am I missing?

diregard :)

on controller, the spirit "cost" goes red. Made me think it wasnt active. When I switched to keyboard and moust, it was OK