C# Script compile error in unity

[DeathFromAbove]

I have this code.

using UnityEngine;
using System.Collections;

public class Spawner : MonoBehaviour {

	public GameObject [] groups ;

	void start(){
		spawnNext ();
	}

	void spawnNext () {
		int i = Random.Range (0, groups.Length);
		
		Increment (groups[i],
		           transform.position,
		           Quaternion.identity); 
	}
}

This program is supposed to take a prefab block and spawn it at the top of my screen, like in Tetris. However, when I run it in Unity it says that there is a compiler error. Is there something wrong with my program or with unity?