It seems like all new themes are missing:

$theme[38]['PATH'] = SM_PATH . 'themes/silver_steel_theme.php';
$theme[38]['NAME'] = 'Silver Steel';
$theme[39]['PATH'] = SM_PATH . 'themes/simple_green_theme.php';
$theme[39]['NAME'] = 'Simple Green';
$theme[40]['PATH'] = SM_PATH . 'themes/wood_theme.php';
$theme[40]['NAME'] = 'Wood';
$theme[41]['PATH'] = SM_PATH . 'themes/bluesome.php';
$theme[41]['NAME'] = 'Bluesome';
$theme[42]['PATH'] = SM_PATH . 'themes/simple_green2.php';
$theme[42]['NAME'] = 'Simple Green 2';
$theme[43]['PATH'] = SM_PATH . 'themes/simple_purple.php';
$theme[43]['NAME'] = 'Simple Purple';
$theme[44]['PATH'] = SM_PATH . 'themes/autumn.php';
$theme[44]['NAME'] = 'Autumn';
$theme[45]['PATH'] = SM_PATH . 'themes/autumn2.php';
$theme[45]['NAME'] = 'Autumn 2';
$theme[46]['PATH'] = SM_PATH . 'themes/blue_on_blue.php';
$theme[46]['NAME'] = 'Blue on Blue';
$theme[47]['PATH'] = SM_PATH . 'themes/classic_blue.php';
$theme[47]['NAME'] = 'Classic Blue';
$theme[48]['PATH'] = SM_PATH . 'themes/classic_blue2.php';
$theme[48]['NAME'] = 'Classic Blue 2';
$theme[49]['PATH'] = SM_PATH . 'themes/powder_blue.php';
$theme[49]['NAME'] = 'Powder Blue';
$theme[50]['PATH'] = SM_PATH . 'themes/techno_blue.php';
$theme[50]['NAME'] = 'Techno Blue';
$theme[51]['PATH'] = SM_PATH . 'themes/turquoise.php';
$theme[51]['NAME'] = 'Turquoise';

It would be helpful to add the numbers used in the config file to the selectbox and overview as well