Plugin error

[omadboy]

I am getting that error.
Its weird that it does this sometimes not always. It appears when I run the program (sometimes).

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;
using System.Collections.Generic;
using System.Linq;
using ArcheBuddy.Bot.Classes;       


namespace DefaultNameSpace{
   public class DefaultClass : Core
   {                    
        private Gps gps;       
       public static string GetPluginAuthor()
       {
           return "dr";
       }

       public static string GetPluginVersion()
       {
           return "1.0.0.0";
       }

       public static string GetPluginDescription()
       {
           return "back";
       }

       //Call on plugin start

       public void PluginRun()
       {             

           if (dist(15414.07, 7683.35, 192.05) > 300)
            
            
            {          
   Thread.Sleep(2000);  
          UsePortalBook();
   Thread.Sleep(1500); 
    gps = new Gps(this); //this - your main class, Core inheritor
    gps.LoadDataBase(Application.StartupPath + "\\plugins\\doctora\\hall.db3");
    gps.onGpsPreMove += gpsPreMove;     
    gps.GpsMove("A");    
  Thread.Sleep(1000);  
        gps.GpsMove("B");       
          Thread.Sleep(1000);  
            gps.GpsMove("C");       
              Thread.Sleep(1000);  
                gps.GpsMove("D");
    Thread.Sleep(1500);        
    CloseGame();


            }
            else
            {
            Log("Cok yakin"); 
            CloseGame();
            }
 
       }    
       

            
        public  void UsePortalBook()  
         {    
            foreach (var port in me.portalBook.getDistricts())
                {
                    if (port.name == "Halo Hollow")
                    {
                        port.OpenPortal();
                        Thread.Sleep(1000);
                        while (me.isCasting || me.isGlobalCooldown)
                            Thread.Sleep(100);
                        Thread.Sleep(2500);
                        UsePortal(getMyPortal());
                        break;
                    }
                }  
         }
                       
         public Creature getMyPortal()
        {
            foreach (var creat in getCreatures())
            {
                if (creat.db.id == 3891 && creat.ownerUniqId == me.uniqId)
                    return creat;
            }
            return null;
        }
   
       

 
      public void gpsPreMove(GpsPoint point)
        {  
        }      

             

     
           
             

       //Call on plugin stop
       public void PluginStop()
       {
       }
   }
}