Getting Problem while executing HQL Query

public static IList<ClsCompany > RetreiveAll()
       {
           IList<ClsCompany> Company = null;
           try
           {
               using (var Session = ClsNhiberateHelper.OpenSession())
               {
                   NHibernate.IQuery Query = Session.CreateQuery("from tblCompany tc order by tc.company ");
                   Company = Query.List<ClsCompany>();
                   return Company;                   
               }
           }
           catch (Exception ex)
           {
               throw new Exception(ex.Message);
           }
       }