error during installation on drupal 5.12

Error during module installation.

STEPS TO REPRODUCE
* downloaded drupal, expanded tarball into .../myapp
* create the directories .../myapp/files and .../myapp/sites/all/modules/, create a cron job for the drupal installation
* go to http://myapp/install.php?profile=default & initialized database, finished admin creation
* downloaded and expanded RPG module into ...myapp/sites/all/modules/
* went to drupal administration > enable modules - enabled all RPG modules except mudslinger and snowball

reviewed error log:
PHP Fatal error: Call to undefined function _rpg_save_all_marked_objects() in ...modules/rpg/rpg.module on line 115

SOLUTION:
in rpg.module, add this line:
require_once(drupal_get_path('module', 'rpg') . '/inc/rpg.db.inc');

after this line at the top:
require_once(drupal_get_path('module', 'rpg') . '/inc/rpg.theme.inc');

reloading the page enabled the module successfully.