Csharp error - PLS help :( | error CS1501

(search the error at the end of the code) code:

    [Command]
    void CmdOnShoot()
    {
        RpcDoShootEffect();
    }

    [ClientRpc]
    void RpcDoShootEffect()
    {
        weaponManager.GetCurrentGraphics().muzzleFlash.Play();
    }

    [Command]
    void CmdOnHit(Vector3 _pos, Vector3 _normal)
    {
        RpcDoHitEffect(_pos, _normal);
    }

    [ClientRpc]
    void RpcDoHitEffect(Vector3 _pos, Vector3 _normal)
    {
        GameObject _hitEffect = (GameObject)Instantiate(weaponManager.GetCurrentGraphics().hitEffectPrefab, _pos, Quaternion.LookRotation(_normal));
        Destroy(_hitEffect, 2f);
    }

    [Client]
	void Shoot (){
        if (!isLocalPlayer)
        {
            return;
        }

        CmdOnShoot();

        Debug.Log("Shoot.");

		RaycastHit _hit;
		if (Physics.Raycast(cam.transform.position, cam.transform.forward, out _hit, currentWeapon.range, mask)) {
			if (_hit.collider.tag == PLAYER_TAG) {
				CmdPlayerShot (_hit.collider.name, currentWeapon.damage);
			}

            CmdOnHit(_hit.point, _hit.normal);
		}
	}

	[Command]
	void CmdPlayerShot(string _playerID, int _damage)
	{
		Debug.Log (_playerID + " has been shot.");

		Player _player = GameManagerOnline.GetPlayer (_playerID);
		_player.RpcTakeDamage(_damage); **<-------- (error here)
	}
}

error code: Assets/OnlineScripts/PlayerShoot.cs(99,11): error CS1501: No overload for method RpcTakeDamage' takes 1’ arguments

The error very explicitly states the problem. You have a method called “RpcTakeDamage”, that unfortunately is not part of the code you posted. When calling it, you pass exactly one argument, but that is not the number of arguments that you need to pass. A small example:

float Add(float a, float b)
{
  return a + b;
}

void Start()
{
  AddFloat(7);
}

The Add function expects two floats, but only gets one. Obviously, the Computer has no idea how to work with this, so the code is invalid.

To solve this, go to where RpcTakeDamage is defined and see what arguments need to be passed, then pass fitting ones.