null refrence

Im trying to emit a particle when a function is called, which it does, except once the particle has been emitted and i next call that function it causes a null?
i cant really figure it out.

ParticleEmitter hitParticles = GameObject.Find(“blood”).GetComponent(typeof(ParticleEmitter)) as ParticleEmitter;

Is your Particle Emitter set to Autodestruct?

-JFFM