error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement

Hi! I pretty new to c# , i trying to make a script to "teleport" the player to another "scene" when it enter a collider,also with a little gui asking him if he want to enter the scene, just press "f",finally removing the little gui when it exit the trigger,but i got this error

TeleporterC.cs(46,41):error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement

Line 46 is the last function OnTriggerExit,with the drawGui variable..

 using UnityEngine;
 using System.Collections;
 
 public class TeleporterC : MonoBehaviour {
     
     public string teleportToMap = "Level1";
     public string spawnPointName = "PlayerSpawn1"; //Use for Move Player to the SpawnPoint Position
     public string toText = ""; //What you want the target location to say on-screen
 
     private bool drawGui = false; //Control for the GUI group layout
 
     void Update(){
 
         if(drawGui == true && Input.GetKeyDown(KeyCode.F)){
             ChangeMap();
         }
     }
 
     void OnTriggerEnter(Collider other){
 
         if(other.tag == "Player"){
             other.GetComponent<StatusC>().spawnPointName = spawnPointName;
             ChangeMap();
         }        
     }
 
     void ChangeMap(){
 
         Application.LoadLevel (teleportToMap);
     }
 
     void OnGui(){
 
         if(drawGui == true){
             GUI.skin.box.fontSize = 18;
             GUI.backgroundColor = Color(255,0,0,0);
             GUI.BeginGroup(Rect(Screen.width /2 - 75,Screen.height /2 - 0,200,75));
             GUI.Box(Rect(0,0,200,25),"Press F to Enter");
             GUI.Box(Rect(0,22,200,25),toText);
             GUI.EndGroup();
         }
     }
 
     void OnTriggerExit(Collider other){
         if(other.tag == "Player"){
             drawGui == false;
         }
     }      
 }

What cause me this error,anyone?

Thank you