particles local to world, I am noob with a problem

So This has been asked before but I did not quite understand the answers.

The link is: http://answers.unity3d.com/questions/352554/particle-system-change-the-velocity-by-script.html

I think I am doing it wrong:

As I am following this as a test to see if it works:

void LateUpdate () {

      ParticleSystem.Particle[] p = new ParticleSystem.Particle[particleSystem.particleCount+1];
      int l = particleSystem.GetParticles(p);
      
      int i = 0;
      while (i < l) {
          p[i].velocity = new Vector3(0, p[i].lifetime / p[i].startLifetime * 10F, 0);
          i++;
      }
  
      particleSystem.SetParticles(p, l);    
      
  }

I tried this to see if it would work.

Is this too difficult for me? As I understand the scripting and can read it just about, and understand the logic, but I am getting this error.

I am trying to create a lava drop to fall off a lava tail, but when it moves the drops just hang in mid air then they fall, and I am trying to get it to form on the tail and then fall behind the tail naturally.

Just not sure how else to solve this problem unless i am missing an obvious function in the particle editor that allows you to do this.