Setting Target For Enemy Inside AI?

Hello,
So I have a transform target and I need to set the target to ym main camera?
How can I do this?
This code gives me the cannot implicitly convert transform into GameObject.
Thanks

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class AdvancedAI : MonoBehaviour
6. {
7.     float distance;
8.    
9.     public float lookAtDistance = 25.0F;
10.     public float chaseRange = 2050.0F;
11.     public float attackRange =4.5F ;
12.     public float moveSpeed = 5.0F;
13.     public float damping = 6.0F;
14.     public float damage = 30.0F;
15.     public float attackRepeatTime = .8F;
16.     public Transform target;
17.     public CharacterController controller;
18.     private float verticalMomentum = 0f;
19.     private float gravity = -9.8f;
20.    
21.     private Vector3 moveDirection = Vector3.zero;
22.     private float attackTime;
23.  
24.  
25.  
26.     //TODO: add in a function to find controller and to locate and assign the player as the target
27.    
28.     void Start()
29.     {
30.         attackTime = Time.time;
31.         target = GameObject.FindWithTag("MainCamera");
32.     }
33.    
34.     void Update()
35.     {
36.         distance = Vector3.Distance(target.position, transform.position);
37.         verticalMomentum += gravity * Time.deltaTime;
38.        
39.         if(distance < lookAtDistance)
40.         {
41.             LookAt();
42.         }
43.        
44.         if (distance < attackRange)
45.         {
46.             AttackPlayer();
47.         }
48.        
49.         else if (distance < chaseRange)
50.         {
51.             ChasePlayer();
52.  
53.         }
54.     }
55.    
56.     void LookAt()
57.     {
58.         Quaternion rotation = Quaternion.LookRotation(target.position - transform.position);
59.         transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * damping);
60.     }
61.    
62.     void ChasePlayer()
63.     {
64.         moveDirection = transform.forward;
65.         moveDirection *= moveSpeed;
66.         moveDirection.y += verticalMomentum * Time.deltaTime;
67.         controller.Move(moveDirection * Time.deltaTime);
68.     }
69.    
70.     void AttackPlayer()
71.     {
72.         //TODO: Need Attack Animations
73.         if (Time.time > attackTime)
74.         {
75.             target.SendMessage("damagePlayer", damage, SendMessageOptions.DontRequireReceiver);
76.             attackTime = Time.time + attackRepeatTime;
77.         }
78.     }
79.    
80.     void ApplyDamage()
81.     {
82.         chaseRange += 15;
83.         moveSpeed += 1;
84.         lookAtDistance += 20;
85.     }
86. }
87.  

 

Any Ideas guys?
If I get this, i'm done my game

 

Code (CSharp):

1. target = GameObject.FindWithTag("MainCamera").transform;

 

your problem is that the target is a Tranform and it needs to be a game object

 

If you shooting at the player to make him get hit when moving just saying. I would just make a 2d/3d cube and make it
transparrent. Then attach it to the target

public game object Target;
drag the cube to the target attachment
place the cube anywhere you want. and attach it
target = Gameobject.Target;
Ta-Da!