null exception error

try
            {
                objFilingCommonEntityciv = Session[Constant.Filed] as CommonEntity;
                if (objFilingCommonEntityciv != null)
                {
                    string a = string.Empty;
                    
                    a = objFilingCommonEntityciv.Type;
                    if (a =="good")
                    {
                        lblnoteName.Text = "MORNING";
                        lblbookValue.Text = "MOrning";
                    }

                    else
                    {
                        lblnoteName.Text = "night";
                        lblbookValue.Text = "night";
                    }
                    
            }
            catch (Exception ex)
            {
                Logger.Error(Error encountered at loaddata, ex);
                throw;
            }