namespace 'global::' already contains a definition for 'EnemyMovement'

I am making the survival game made by Unity at their 2014 convention, using Unity 4.6, and I am getting error CS0101: The namespace 'global::' already contains a definition for 'EnemyMovement'. My code is shown below

 using UnityEngine;
 using System.Collections;
 
 public class EnemyMovement : MonoBehaviour;
 {
     Transform player;                
     //PlayerHealth playerHealth;        
     //EnemyHealth enemyHealth;        
     NavMeshAgent nav;            
 
 
     void Awake ()
     {
         player = GameObject.FindGameObjectWithTag ("Player").transform;
         //playerHealth = player.GetComponent <PlayerHealth> ();
         //enemyHealth = GetComponent <EnemyHealth> ();
         nav = GetComponent <NavMeshAgent> ();
     }
 
 
     void Update ()
     {
         //if(enemyHealth.currentHealth > 0 && playerHealth.currentHealth > 0)
         //{
             nav.SetDestination (player.position);
         //}
         //else
         //{
         //      nav.enabled = false;
         //}
     }
 }