When a query using the LOCK TABLES MySQL command is issued through PEAR, it believes it returns an error even if this is not true. For instance,

<?
require_once("DB.php");
$db = DB::connect("mysql://root@localhost/DSI");
$rs = $db->query("LOCK TABLE persona READ");
print_r($rs);
?>

leaves in the log

[04-Nov-2001 23:14:17] PHP Warning:  Undefined offset:  0 in /usr/share/php/DB/common.php on line 126
and outputs

db_error Object
(
    [error_message_prefix] => 
    [error_prepend] => 
    [error_append] => 
    [mode] => 1
    [level] => 1024
    [code] => -1
    [message] => DB Error: unknown error
    [debuginfo] => 
    [userinfo] => LOCK TABLE persona READ
    [callback] => 
)