Please make below change:
file:admin/modules.php
find below :

case 'save':
while (list($key, $value) = each($HTTP_POST_VARS['configuration'])) {
if( is_array( $value ) ){
$value = implode( ", ", $value);
$value = ereg_replace (", --none--", "", $value);
}
tep_db_query("update " . TABLE_CONFIGURATION . " set configuration_value = '" . $value . "' where configuration_key = '" . $key . "'");
}

Append this code:
// UPDATE CONFIGURATION CACHES
updateConfiguration();

thank you.

More...