I checked configure_bts.php and all seems to be in order:
<?php
// BTS defines added 2003/12/23
define('DIR_WS_TEMPLATES', $tplDir . '/' );
define('DIR_WS_CONTENT', DIR_WS_TEMPLATES . 'content/');
define('DIR_WS_JAVASCRIPT', DIR_WS_INCLUDES . 'javascript/');
define('DIR_WS_BOX_TEMPLATES', DIR_WS_TEMPLATES . 'boxes/');
// define the templatenames used in the project
define('TEMPLATENAME_BOX', 'box.tpl.php');
define('TEMPLATENAME_MAIN_PAGE', 'main_page.tpl.php');
define('TEMPLATENAME_POPUP', 'popup.tpl.php');
define('TEMPLATENAME_STATIC', 'static.tpl.php');
?>
and I alsp checked the application_top.php but am not sure what I'm looking for there.