Директория для phpnuke: nuke/db/db.php'. В файле db.php внизу есть код: 

Код:
$db = new sql_db($dbhost, $dbuname, $dbpass, $dbname, false); 
if(!$db->db_connect_id) { 
    die("<br><br><center><img src=images/logo.gif><br><br><b>There seems to be a problem with the MySQL server, sorry for the inconvenience.<br><br>We should be back shortly.</center></b>");


Поменяйте его на: 

Код:
$db = new sql_db($dbhost, $dbuname, $dbpass, $dbname, false); 
mysql_query ("set character_set_results='cp1251'"); 
if(!$db->db_connect_id) { 
    die("<br><br><center><img src=images/logo.gif><br><br><b>There seems to be a problem with the MySQL server, sorry for the inconvenience.<br><br>We should be back shortly.</center></b>");