Magento – Maximum function nesting level , what it means

when i add

    Mage::log($name, null, 'events.log', true);

in the function of dispatchEvent()

public static function dispatchEvent($name, array $data = array())
{
    Mage::log($name, null, 'events.log', true);
    Varien_Profiler::start('DISPATCH EVENT:'.$name);
    $result = self::app()->dispatchEvent($name, $data);
    Varien_Profiler::stop('DISPATCH EVENT:'.$name);
    return $result;
}

the following error i got

( ! ) Fatal error: Maximum function nesting level of '100' reached,
aborting! in
E:\wamp\www\magento\app\code\core\Mage\Core\Model\Abstract.php on line
119

how to avoid this?