If this is mysql then please update php and show all errors and warnings.

pardon me, there is no problem while PDO methods running in functions. but i can't execute recursive queries with same PDO object; php triggers "Invalid argument supplied for foreach" error.

example:
foreach ($qDB->query('SELECT NOW() AS z') as $row) {
  foreach ($qDB->query('SELECT NOW() AS x') as $subrow) { // Invalid argument supplied for foreach()
    echo $subrow['x'];
  }
}


my code:
foreach ($qDB->query('SELECT entities.alias, entities.fieldidx FROM entities WHERE entities.fieldtype=\'s\' AND (entities.parenttype=\'s\' AND entities.parentidx=\'0\')', PDO_FETCH_ASSOC) as $tRow) {
	// addToStorage('s' . $tRow['fieldidx']);
	$x = $qDB->prepare('SELECT * FROM articles');
	exit($x);
	echo $system->strings->format('<td><a href="http://{0}.turkishqf.org/"{1}>{2}</a></td>', $tRow['alias'], (($pRequestDomain == $tRow['alias']) ? ' class="act"' : ''), $pStorage['s' . $tRow['fieldidx']]['name']);
}

to repeat the Q: ARE YOU USING MYSQL?

yes, mysql-max-4.1.12 on freebsd 4.7

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

ATM parallel queries are not available using mysql. Wait for someone to write a decent pdo_mysql driver, use a decent rdbms like postgres or use fetchall().

FYI, you should use fetchAll().
The PDO MYSQL driver *is* decent, and what you're trying to do is not supported by most major databases.