6 theme calls to theme_install_page()

install_already_done_error in drupal-6.x/install.php
Show an error page when Drupal has already been installed.
install_change_settings in drupal-6.x/install.php
Configure and rewrite settings.php.
install_main in drupal-6.x/install.php
The Drupal installation happens in a series of steps. We begin by verifying that the current environment meets our minimum requirements. We then go on to verify that settings.php is properly configured. From there we connect to the configured database…
install_no_profile_error in drupal-6.x/install.php
Show an error page when there are no profiles available.
install_select_locale in drupal-6.x/install.php
Allow admin to select which locale to use for the current profile.
install_select_profile in drupal-6.x/install.php
Allow admin to select which profile to install.