Help, Pally/crusader problem

[Natchios]

ok im lvl 15 and i got 10 celestial and i cant get my Divine Intervention to work, it spawned the dude the first time i used it but it hasnt worked since.
Bug or am i doin something wrong?

[GeorgeKeith]

It's mana regenerated yet?

[Gorn]

Careful not to cast the spell into a wall or object, give the spell room to blossom.