[horde] Prefs - error

[growe at woodvale.on.ca]

If in the /var/www/html/horde/config/horde.php file I write...
$conf['prefs']['driver'] = 'sql';
instead of...
$conf['prefs']['driver'] = 'none';
I get this error...
Fatal error: Call to undefined function: iswarning() 
in /var/www/html/horde/lib/Prefs/sql.php on line 101


In the horde.php I also have this...
 $conf['prefs']['params']['phptype'] = 'mysql';
 $conf['prefs']['params']['hostspec'] = 'localhost';
 $conf['prefs']['params']['username'] = 'horde';
 $conf['prefs']['params']['password'] = 'my_password';
 $conf['prefs']['params']['database'] = 'horde';
 $conf['prefs']['params']['table'] = 'horde_prefs';


If you can tell me why I am getting the error I would be very happy...

Thanks,

Glenn