Help with selecting objects through raycast in multiplayer game

Hello, i've been programming for some time now and i decided to start a multiplayer project. It's a 2D rpg game where you battle by selecting enemies and then cast abilities on them. So far everything has gone smoothly by following some toturials and applying what i learned from them to the project, but now i seem to be stuck with an error. The error is: UNetWeaver error: Command function [Raycast:CmdClickSelect] must have a void return type. UnityEngine.Debug:LogError(Object) Unity.UNetWeaver.Log:Error(String) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/Program.cs:20) Unity.UNetWeaver.NetworkBehaviourProcessor:ProcessMethods() (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetBehaviourProcessor.cs:1240) Unity.UNetWeaver.NetworkBehaviourProcessor:Process() (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetBehaviourProcessor.cs:56) Unity.UNetWeaver.Weaver:ProcessNetworkBehaviourType(TypeDefinition) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetWeaver.cs:1064) Unity.UNetWeaver.Weaver:CheckNetworkBehaviour(TypeDefinition) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetWeaver.cs:1549) Unity.UNetWeaver.Weaver:Weave(String, IEnumerable`1, IAssemblyResolver, String, String, String) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetWeaver.cs:1658) Unity.UNetWeaver.Weaver:WeaveAssemblies(IEnumerable`1, IEnumerable`1, IAssemblyResolver, String, String, String) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/UNetWeaver.cs:1748) Unity.UNetWeaver.Program:Process(String, String, String, String[], String[], IAssemblyResolver, Action`1, Action`1) (at C:/buildslave/unity/build/Extensions/Networking/Weaver/Program.cs:34) UnityEditor.Scripting.Serialization.Weaver:WeaveUnetFromEditor(String, String, String, String, Boolean)

And it also comes out saying: Failure generating network code. UnityEditor.Scripting.Serialization.Weaver:WeaveUnetFromEditor(String, String, String, String, Boolean)

here's the code:

using UnityEngine; using System.Collections; using UnityEngine.Networking;

public class Raycast : NetworkBehaviour {

 public GameObject SelectedEnemy;


 [SerializeField]
 private Frost frostAbility;
 [SerializeField]
 private Fireball fireballAbility;
 [SerializeField]
 private Shockwave shockwaveAbility;

 public bool casting = false;



 void Update()
 {


     if (Input.GetButtonDown("Fire1"))
     {
         //Raycast
         Vector2 rayPos = new Vector2(Camera.main.ScreenToWorldPoint(Input.mousePosition).x, Camera.main.ScreenToWorldPoint(Input.mousePosition).y);
         RaycastHit2D hit = Physics2D.Raycast(rayPos, Vector2.zero, 0f);
         CmdClickSelect(hit.collider.gameObject);
     }
     if (Input.GetKeyDown("1") && SelectedEnemy != null && casting == false)
     {
         StartCoroutine(CastTime(frostAbility.castTime, frostAbility.manaCost, frostAbility.abilityName));
         casting = true;

     }
     if (Input.GetKeyDown("2") && SelectedEnemy != null && casting == false)
     {
         StartCoroutine(CastTime(fireballAbility.castTime, fireballAbility.manaCost, fireballAbility.abilityName));
         casting = true;
     }
     if (Input.GetKeyDown("3") && SelectedEnemy != null && casting == false)
     {
         StartCoroutine(CastTime(shockwaveAbility.castTime, shockwaveAbility.manaCost, shockwaveAbility.abilityName));
         casting = true;
     }
 }

 //wait for casttime
 IEnumerator CastTime(float _castTime, float _manaCost, string _abilityName)
 {
     yield return new WaitForSeconds(_castTime);
     CmdDealEnemyDamage(GetComponent<Player>().magic, _manaCost, _abilityName);
     casting = false;
 }

 //send damage to the selected target
 [Command]
 void CmdDealEnemyDamage(float _damageAmount, float _manaCost, string _abilityName)
 {
     if (GetComponent<Player>().currentMana > _manaCost)
     {
         Debug.Log("Used " + _abilityName);
         SelectedEnemy.GetComponent<Enemy>().RpcEnemyTakeDamage(_damageAmount);
         GetComponent<Player>().currentMana -= _manaCost;
     }
     else
     {
         return;
     }
 }

 //this is where the problem is
 [Command]
 public GameObject CmdClickSelect(GameObject _hit)
 {

     //if enemy is hit select that enemy
     if (_hit && _hit.gameObject.tag == "Enemy" && SelectedEnemy != _hit.gameObject)
     {

         SelectedEnemy.GetComponent<Enemy>().CmdEnemySelectPlayer(this.gameObject);
         Debug.Log(_hit.gameObject.name);
         return _hit.gameObject;
     }
     return null;


 }

}

So if anybody can help me with this error or if someone has a better way of doing this then please answer. Also feel free to tell me if you see i have done something stupid in the script :)