how to call setVelocity method Character Motor script from other script?

Hello!

I'm using the Firt Person Controller that comes with unity, and y want to implement a jetpack, but it was not possible for me to have a reference of the CharacterMotor reference in order to call methods from it to change the velocity...

i think my problem is that my script is in C#, and CharacterMotor is written in Javascript... but I have no idea how this could be a problem...

this is my script, very simple:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(CharacterMotor))]
 
 public class JetPack : MonoBehaviour
 {
     CharacterMotor motor;
     
     void Awake()
     {
         motor = GetComponent<CharacterMotor>();
     }
     
     // Update is called once per frame
     void Update()
     {
         //this do not work :(
         //object grounded = motor.IsGrounded();
         //if(grounded)
         //    Debug.Log("AAA");
         
         if(Input.GetButtonDown("Fire2"))
             motor.SetVelocity(Vector3.up);
     }
     
     
     //this works
     void OnJump()
     {
         Debug.Log("OnJump");
     }
     
     //this works
     void OnLand()
     {
         Debug.Log("OnLand");
     }
 }
 

but when i try to compile, it shows this error:

 JetPack.cs(31,31): Error CS0584: Internal compiler error: $SubtractNewPlatformVelocity$3 (CS0584) (Assembly-CSharp)
 
 JetPack.cs(31,31): Error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement (CS0201) (Assembly-CSharp)

on this line

 motor.SetVelocity(Vector3.up);

what can i do?