diff --git a/app/ae_obj_types_def.py b/app/ae_obj_types_def.py
index c099b47..a8b57c0 100644
--- a/app/ae_obj_types_def.py
+++ b/app/ae_obj_types_def.py
@@ -103,7 +103,19 @@ obj_type_kv_li = {
         'mdl': Event_Badge_Base, 'mdl_default': Event_Badge_Basic_Base, 'mdl_alt': Event_Badge_Basic_Base
         },
     'event_presenter': {
-        'tbl': 'event_presenter', 'tbl_default': 'v_event_presenter', 'tbl_update': 'event_presenter', 'mdl': Event_Presenter_Base, 'mdl_default': Event_Presenter_Base, 'mdl_in': Event_Presenter_Base, 'mdl_out': Event_Presenter_Out_Base
+        'tbl': 'event_presenter', 'tbl_default': 'v_event_presenter', 'tbl_update': 'event_presenter', 'mdl': Event_Presenter_Base, 'mdl_default': Event_Presenter_Base, 'mdl_in': Event_Presenter_Base, 'mdl_out': Event_Presenter_Out_Base,
+        'exp_default': [
+            'event_presenter_id_random',
+            # 'account_id_random',
+            'title_names', 'given_name', 'middle_name', 'family_name', 'designations',
+            'professional_title', 'full_name',
+            'affiliations',
+            'email', 'biography',
+            # 'image_li_json', 'social_li_json',
+            'agree',
+            'comments',
+            'enable', 'hide', 'priority', 'sort', 'group', 'notes', 'created_on', 'updated_on',
+            ],
         },
 } # New 2024-04-23
 # obj_type_kv_li['example_template'] = {'tbl': 'example_template', 'tbl_default': 'v_example_template', 'tbl_update': 'example_template', 'mdl': Example_Template_Base, 'mdl_in': Example_Template_In_Base, 'mdl_out': Example_Template_Out_Base  }
diff --git a/app/lib_general.py b/app/lib_general.py
index d5a801a..16d1b7e 100644
--- a/app/lib_general.py
+++ b/app/lib_general.py
@@ -382,6 +382,11 @@ def create_export_file(
     data_dataframe = pandas.DataFrame(data_dict_list)
     log.debug(data_dataframe)
 
+    missing_cols = [col for col in column_name_li if col not in data_dataframe.columns]
+    if missing_cols:
+        raise KeyError(f"The following columns are not found in the DataFrame: {', '.join(missing_cols)}")
+
+    # Need to deal with this error: KeyError("Not all names specified in 'columns' are found")
     try:
         if export_type == 'CSV':
             log.info('Saving dataframe to CSV file')
@@ -390,7 +395,7 @@ def create_export_file(
             tmp_file_path = os.path.join(subdir_path,filename_w_ext)
             data_dataframe.to_csv(
                 full_dest_path,
-                # na_rep='NULL',
+                na_rep='NULL',
                 columns=column_name_li,
                 index=False,
                 # errors='ignore',
@@ -403,7 +408,7 @@ def create_export_file(
             # This should ignore unknown columns
             data_dataframe.to_excel(
                 full_dest_path,
-                # na_rep='NULL',
+                na_rep='NULL',
                 columns=column_name_li,
                 index=False,
                 # engine='openpyxl',