after publish and uploading to server am geeting this error.Server Error in '/' Application. Object reference not set to an instance of an object. How to solve that

Server Error in '/' Application. Object reference not set to an instance of an object. my code is this
 protected void Page_Load(object sender, EventArgs e)     {         if (!Page.IsPostBack)         {             if (Request.QueryString["lattitude"] != null && Request.QueryString["longitude"] != null && Request.QueryString["userid"] != null && Request.QueryString["imei"] != null)             {                 addBusinessopportunities objaddmac = new addBusinessopportunities();         & ...