Rigidbody script throwing error CS0246: The type or namespace name `MouseLook' could not be found. Are you missing an assembly reference?

Hello devs!

I've been stuck on this for the last 3 hours and I really need some help.

Now, I have 2 scripts that are giving me some grief, the RigidbodyFirstPersonController.cs and the MouseLook.cs scripts. On my player model, I have a custom script for the controls and finally got working, so I moved onto the camera (as it would spin way out and cause a "screen position out of view frustum" error and crash the game) and was following this tutorial:

https://www.youtube.com/watch?v=BBS2nIKzmbw

And I was only following the Camera's side of the tutorial (as I already had my script and just really needed help with the camera) and I'm following the tutorial and get an error for the TargetRotation (and you can see others are stuck on this too) and after looking up definitions and trying to find replacement code for that line and doing everything I can think of, I get frustrated, make a copy of the file, disable and remove it, then added the MouseLook.cs file (which I think is the standard asset that comes with Unity's package) and this is when the error started.

Again, I keep checking between the two scripts (I did not drag and drop the RigidbodyFirstPersonController script on there, I clicked Add Component, and selected it from the list) and I still can't get it to work. So I try adding the rigidbody's script on there, this time by dragging and dropping it, thinking I could fix it in the inspector by assigning the main camera and the MouseLook, except I'm unable to select the MouseLook script.

I then disable the MouseLook file and remove the component, only to have RigidBody's script throw the same error again. I remove the MouseLook script from the Camera and the rigidbody script (I reset and put it to how it was when it was working) but it still showed this error.

I'm going to put a copy of both the RigidbodyFirstPersonController and the MouseLook scripts, because it never had this problem before and I'm really stuck here :(

RigidbodyFirstPersonController.cs:

 using System;
 using UnityEngine;
 using UnityStandardAssets.CrossPlatformInput;
 
 namespace UnityStandardAssets.Characters.FirstPerson
 {
     [RequireComponent(typeof (Rigidbody))]
     [RequireComponent(typeof (CapsuleCollider))]
     public class RigidbodyFirstPersonController : MonoBehaviour
     {
         [Serializable]
         public class MovementSettings
         {
             public float ForwardSpeed = 8.0f;   // Speed when walking forward
             public float BackwardSpeed = 4.0f;  // Speed when walking backwards
             public float StrafeSpeed = 4.0f;    // Speed when walking sideways
             public float RunMultiplier = 2.0f;   // Speed when sprinting
             public KeyCode RunKey = KeyCode.LeftShift;
             public float JumpForce = 30f;
             public AnimationCurve SlopeCurveModifier = new AnimationCurve(new Keyframe(-90.0f, 1.0f), new Keyframe(0.0f, 1.0f), new Keyframe(90.0f, 0.0f));
             [HideInInspector] public float CurrentTargetSpeed = 8f;
 
 #if !MOBILE_INPUT
             private bool m_Running;
 #endif
 
             public void UpdateDesiredTargetSpeed(Vector2 input)
             {
                 if (input == Vector2.zero) return;
                 if (input.x > 0 || input.x < 0)
                 {
                     //strafe
                     CurrentTargetSpeed = StrafeSpeed;
                 }
                 if (input.y < 0)
                 {
                     //backwards
                     CurrentTargetSpeed = BackwardSpeed;
                 }
                 if (input.y > 0)
                 {
                     //forwards
                     //handled last as if strafing and moving forward at the same time forwards speed should take precedence
                     CurrentTargetSpeed = ForwardSpeed;
                 }
 #if !MOBILE_INPUT
                 if (Input.GetKey(RunKey))
                 {
                     CurrentTargetSpeed *= RunMultiplier;
                     m_Running = true;
                 }
                 else
                 {
                     m_Running = false;
                 }
 #endif
             }
 
 #if !MOBILE_INPUT
             public bool Running
             {
                 get { return m_Running; }
             }
 #endif
         }
 
 
         [Serializable]
         public class AdvancedSettings
         {
             public float groundCheckDistance = 0.01f; // distance for checking if the controller is grounded ( 0.01f seems to work best for this )
             public float stickToGroundHelperDistance = 0.5f; // stops the character
             public float slowDownRate = 20f; // rate at which the controller comes to a stop when there is no input
             public bool airControl; // can the user control the direction that is being moved in the air
             [Tooltip("set it to 0.1 or more if you get stuck in wall")]
             public float shellOffset; //reduce the radius by that ratio to avoid getting stuck in wall (a value of 0.1f is nice)
         }
 
 
         public Camera cam;
         public MovementSettings movementSettings = new MovementSettings();
         public MouseLook mouseLook = new MouseLook();
         public AdvancedSettings advancedSettings = new AdvancedSettings();
 
 
         private Rigidbody m_RigidBody;
         private CapsuleCollider m_Capsule;
         private float m_YRotation;
         private Vector3 m_GroundContactNormal;
         private bool m_Jump, m_PreviouslyGrounded, m_Jumping, m_IsGrounded;
 
         public RigidbodyFirstPersonController(MouseLook mouseLook)
         {
             this.mouseLook = mouseLook;
         }
 
         public Vector3 Velocity
         {
             get { return m_RigidBody.velocity; }
         }
 
         public bool Grounded
         {
             get { return m_IsGrounded; }
         }
 
         public bool Jumping
         {
             get { return m_Jumping; }
         }
 
         public bool Running
         {
             get
             {
  #if !MOBILE_INPUT
                 return movementSettings.Running;
 #else
                 return false;
 #endif
             }
         }
 
 
         private void Start()
         {
             m_RigidBody = GetComponent<Rigidbody>();
             m_Capsule = GetComponent<CapsuleCollider>();
             mouseLook.Init (transform, cam.transform);
         }
 
 
         private void Update()
         {
             RotateView();
 
             if (CrossPlatformInputManager.GetButtonDown("Jump") && !m_Jump)
             {
                 m_Jump = true;
             }
         }
 
 
         private void FixedUpdate()
         {
             GroundCheck();
             Vector2 input = GetInput();
 
             if ((Mathf.Abs(input.x) > float.Epsilon || Mathf.Abs(input.y) > float.Epsilon) && (advancedSettings.airControl || m_IsGrounded))
             {
                 // always move along the camera forward as it is the direction that it being aimed at
                 Vector3 desiredMove = cam.transform.forward*input.y + cam.transform.right*input.x;
                 desiredMove = Vector3.ProjectOnPlane(desiredMove, m_GroundContactNormal).normalized;
 
                 desiredMove.x = desiredMove.x*movementSettings.CurrentTargetSpeed;
                 desiredMove.z = desiredMove.z*movementSettings.CurrentTargetSpeed;
                 desiredMove.y = desiredMove.y*movementSettings.CurrentTargetSpeed;
                 if (m_RigidBody.velocity.sqrMagnitude <
                     (movementSettings.CurrentTargetSpeed*movementSettings.CurrentTargetSpeed))
                 {
                     m_RigidBody.AddForce(desiredMove*SlopeMultiplier(), ForceMode.Impulse);
                 }
             }
 
             if (m_IsGrounded)
             {
                 m_RigidBody.drag = 5f;
 
                 if (m_Jump)
                 {
                     m_RigidBody.drag = 0f;
                     m_RigidBody.velocity = new Vector3(m_RigidBody.velocity.x, 0f, m_RigidBody.velocity.z);
                     m_RigidBody.AddForce(new Vector3(0f, movementSettings.JumpForce, 0f), ForceMode.Impulse);
                     m_Jumping = true;
                 }
 
                 if (!m_Jumping && Mathf.Abs(input.x) < float.Epsilon && Mathf.Abs(input.y) < float.Epsilon && m_RigidBody.velocity.magnitude < 1f)
                 {
                     m_RigidBody.Sleep();
                 }
             }
             else
             {
                 m_RigidBody.drag = 0f;
                 if (m_PreviouslyGrounded && !m_Jumping)
                 {
                     StickToGroundHelper();
                 }
             }
             m_Jump = false;
         }
 
 
         private float SlopeMultiplier()
         {
             float angle = Vector3.Angle(m_GroundContactNormal, Vector3.up);
             return movementSettings.SlopeCurveModifier.Evaluate(angle);
         }
 
 
         private void StickToGroundHelper()
         {
             RaycastHit hitInfo;
             if (Physics.SphereCast(transform.position, m_Capsule.radius * (1.0f - advancedSettings.shellOffset), Vector3.down, out hitInfo,
                                    ((m_Capsule.height/2f) - m_Capsule.radius) +
                                    advancedSettings.stickToGroundHelperDistance, Physics.AllLayers, QueryTriggerInteraction.Ignore))
             {
                 if (Mathf.Abs(Vector3.Angle(hitInfo.normal, Vector3.up)) < 85f)
                 {
                     m_RigidBody.velocity = Vector3.ProjectOnPlane(m_RigidBody.velocity, hitInfo.normal);
                 }
             }
         }
 
 
         private Vector2 GetInput()
         {
             
             Vector2 input = new Vector2
                 {
                     x = CrossPlatformInputManager.GetAxis("Horizontal"),
                     y = CrossPlatformInputManager.GetAxis("Vertical")
                 };
             movementSettings.UpdateDesiredTargetSpeed(input);
             return input;
         }
 
 
         private void RotateView()
         {
             //avoids the mouse looking if the game is effectively paused
             if (Mathf.Abs(Time.timeScale) < float.Epsilon) return;
 
             // get the rotation before it's changed
             float oldYRotation = transform.eulerAngles.y;
 
             mouseLook.LookRotation (transform, cam.transform);
 
             if (m_IsGrounded || advancedSettings.airControl)
             {
                 // Rotate the rigidbody velocity to match the new direction that the character is looking
                 Quaternion velRotation = Quaternion.AngleAxis(transform.eulerAngles.y - oldYRotation, Vector3.up);
                 m_RigidBody.velocity = velRotation*m_RigidBody.velocity;
             }
         }
 
         /// sphere cast down just beyond the bottom of the capsule to see if the capsule is colliding round the bottom
         private void GroundCheck()
         {
             m_PreviouslyGrounded = m_IsGrounded;
             RaycastHit hitInfo;
             if (Physics.SphereCast(transform.position, m_Capsule.radius * (1.0f - advancedSettings.shellOffset), Vector3.down, out hitInfo,
                                    ((m_Capsule.height/2f) - m_Capsule.radius) + advancedSettings.groundCheckDistance, Physics.AllLayers, QueryTriggerInteraction.Ignore))
             {
                 m_IsGrounded = true;
                 m_GroundContactNormal = hitInfo.normal;
             }
             else
             {
                 m_IsGrounded = false;
                 m_GroundContactNormal = Vector3.up;
             }
             if (!m_PreviouslyGrounded && m_IsGrounded && m_Jumping)
             {
                 m_Jumping = false;
             }
         }
     }
 }

MouseLook.cs:

 using System;
 using UnityEngine;
 using UnityStandardAssets.CrossPlatformInput;
 
 namespace UnityStandardAssets.Characters.FirstPerson
 {
     [Serializable]
     public class MouseLook : MonoBehaviour 
     {
         public float XSensitivity = 2f;
         public float YSensitivity = 2f;
         public bool clampVerticalRotation = true;
         public float MinimumX = -90F;
         public float MaximumX = 90F;
         public bool smooth;
         public float smoothTime = 5f;
         public bool lockCursor = true;
 
 
         private Quaternion m_CharacterTargetRot;
         private Quaternion m_CameraTargetRot;
         private bool m_cursorIsLocked = true;
 
         public void Init(Transform character, Transform camera)
         {
             m_CharacterTargetRot = character.localRotation;
             m_CameraTargetRot = camera.localRotation;
         }
 
 
         public void LookRotation(Transform character, Transform camera)
         {
             float yRot = CrossPlatformInputManager.GetAxis("Mouse X") * XSensitivity;
             float xRot = CrossPlatformInputManager.GetAxis("Mouse Y") * YSensitivity;
 
             m_CharacterTargetRot *= Quaternion.Euler (0f, yRot, 0f);
             m_CameraTargetRot *= Quaternion.Euler (-xRot, 0f, 0f);
 
             if(clampVerticalRotation)
                 m_CameraTargetRot = ClampRotationAroundXAxis (m_CameraTargetRot);
 
             if(smooth)
             {
                 character.localRotation = Quaternion.Slerp (character.localRotation, m_CharacterTargetRot,
                     smoothTime * Time.deltaTime);
                 camera.localRotation = Quaternion.Slerp (camera.localRotation, m_CameraTargetRot,
                     smoothTime * Time.deltaTime);
             }
             else
             {
                 character.localRotation = m_CharacterTargetRot;
                 camera.localRotation = m_CameraTargetRot;
             }
 
             UpdateCursorLock();
         }
 
         public void SetCursorLock(bool value)
         {
             lockCursor = value;
             if(!lockCursor)
             {//we force unlock the cursor if the user disable the cursor locking helper
                 Cursor.lockState = CursorLockMode.None;
                 Cursor.visible = true;
             }
         }
 
         public void UpdateCursorLock()
         {
             //if the user set "lockCursor" we check & properly lock the cursor
             if (lockCursor)
                 InternalLockUpdate();
         }
 
         private void InternalLockUpdate()
         {
             if(Input.GetKeyUp(KeyCode.Escape))
             {
                 m_cursorIsLocked = false;
             }
             else if(Input.GetMouseButtonUp(0))
             {
                 m_cursorIsLocked = true;
             }
 
             if (m_cursorIsLocked)
             {
                 Cursor.lockState = CursorLockMode.Locked;
                 Cursor.visible = false;
             }
             else if (!m_cursorIsLocked)
             {
                 Cursor.lockState = CursorLockMode.None;
                 Cursor.visible = true;
             }
         }
 
         Quaternion ClampRotationAroundXAxis(Quaternion q)
         {
             q.x /= q.w;
             q.y /= q.w;
             q.z /= q.w;
             q.w = 1.0f;
 
             float angleX = 2.0f * Mathf.Rad2Deg * Mathf.Atan (q.x);
 
             angleX = Mathf.Clamp (angleX, MinimumX, MaximumX);
 
             q.x = Mathf.Tan (0.5f * Mathf.Deg2Rad * angleX);
 
             return q;
         }
 
     }
 }

I'm also using Unity 2018.10f1 because any time I try to use newer versions, it ruins the project completely.