Same problem here, database is not created. Has been working correctly until recently. Have just installed 2.73. Have tried to return date format to default and also to reactivate several times, but no success. Getting the following error:
WordPress database error Table ‘blog.wp_useronline’ doesn’t exist for query SELECT * FROM wp_useronline made by require, require_once, include, get_footer, locate_template, load_template, require_once, suffusion_before_end_container, do_action, call_user_func_array, suffusion_print_right_sidebars, get_sidebar, locate_template, load_template, require_once, dynamic_sidebar, call_user_func_array, WP_Widget->display_callback, scbWidget->widget, UserOnline_Widget->content, get_users_browsing_site, UserOnline_Template->compact_list, referer: https://www.viajeros.dyndns.info/blog/wp-admin/plugins.php?activate=true&plugin_status=recent&paged=1
Please help.