changed
1.
function my_em_placeholder_mod($replace, $EM_category, $result){ to function my_em_placeholder_mod($replace, $EM_Category, $result){
2.
dbem_category_event_list_item_header_format to dbem_category_list_item_header_format
3.
dbem_category_event_list_item_format to dbem_category_list_item_format
4.
dbem_category_event_list_item_footer_format to dbem_category_list_item_footer_format
5.
dbem_category_no_events_message to dbem_no_categories_message