Particles not appearing on impact, muzzle flash problems?

I'm having a problem with my muzzle flash and particles. I'm following the fps tutorial. I'm trying to use the Sparks prefab as my particles, and I set them as a child object of my gun. Also, I assigned muzzle_flash(the child of my gun) as my muzzle flash animation. However, when I shoot in the game I just get a white box as my muzzle flash. Also, my gun doesn't hit anything. I don't see sparks anywhere. I am using this shooting code for my machine gun:

var range = 100.0; var fireRate = 0.05; var force = 10.0; var damage = 5.0; var bulletsPerClip = 40; var clips = 20; var reloadTime = 0.5; private var hitParticles : ParticleEmitter; var muzzleFlash : Renderer;

private var bulletsLeft : int = 0; private var nextFireTime = 0.0; private var m_LastFrameShot = -1;

function Start () { hitParticles = GetComponentInChildren(ParticleEmitter);

 // We don't want to emit particles all the time, only when we hit something.
 if (hitParticles)
     hitParticles.emit = false;
 bulletsLeft = bulletsPerClip;

}

function LateUpdate() { if (muzzleFlash) { // We shot this frame, enable the muzzle flash if (m_LastFrameShot == Time.frameCount) { muzzleFlash.transform.localRotation = Quaternion.AngleAxis(Random.value * 360, Vector3.forward); muzzleFlash.enabled = true;

         if (audio) {
             if (!audio.isPlaying)
                 audio.Play();
             audio.loop = true;
         }
     } else {
     // We didn't, disable the muzzle flash
         muzzleFlash.enabled = false;
         enabled = false;

         // Play sound
         if (audio)
         {
             audio.loop = false;
         }
     }
 }

}

function Fire () { if (bulletsLeft == 0) return;

 // If there is more than one bullet between the last and this frame
 // Reset the nextFireTime
 if (Time.time - fireRate > nextFireTime)
     nextFireTime = Time.time - Time.deltaTime;

 // Keep firing until we used up the fire time
 while( nextFireTime < Time.time && bulletsLeft != 0) {
     FireOneShot();
     nextFireTime += fireRate;
 }

}

function FireOneShot () { var direction = transform.TransformDirection(Vector3.forward); var hit : RaycastHit;

 // Did we hit anything?
 if (Physics.Raycast (transform.position, direction, hit, range)) {
     // Apply a force to the rigidbody we hit
     if (hit.rigidbody)
         hit.rigidbody.AddForceAtPosition(force * direction, hit.point);

     // Place the particle system for spawing out of place where we hit the surface!
     // And spawn a couple of particles
     if (hitParticles) {
         hitParticles.transform.position = hit.point;
         hitParticles.transform.rotation = Quaternion.FromToRotation(Vector3.up, hit.normal);
         hitParticles.Emit();
     }

     // Send a damage message to the hit object          
     hit.collider.SendMessageUpwards("ApplyDamage", damage, SendMessageOptions.DontRequireReceiver);
 }

 bulletsLeft--;

 // Register that we shot this frame,
 // so that the LateUpdate function enabled the muzzleflash renderer for one frame
 m_LastFrameShot = Time.frameCount;
 enabled = true;

 // Reload gun in reload Time        
 if (bulletsLeft == 0)
     Reload();           

}

function Reload () {

 // Wait for reload time first - then add more bullets!
 yield WaitForSeconds(reloadTime);

 // We have a clip left reload
 if (clips > 0) {
     clips--;
     bulletsLeft = bulletsPerClip;
 }

}

function GetBulletsLeft () { return bulletsLeft; }