Regex is not the tool for this. HTML tag structure is too complex, for basic Regex, and you should try some HTML DOM library like PHP Simple HTML DOM Parser, to do HTML DOM work.
$html = file_get_html('http://pastebin.com/raw.php?i=a3g3G1uE');
foreach($html->find('b:loop') as $element)
echo $element->values. '<br>';
Look at my example for your specific case and read documentation.