Estoy tratando de analizar el contenido de cualquier url. Que no debe contentar ningún código html. Esto funciona bien, pero da un montón de errores al leer el contenido en la url dada. ¿Cómo eliminar esta advertencia?

<?php
$url= 'http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page';
$doc = new DOMDocument();
$doc->loadHTMLFile($url);
$xpath = new DOMXPath($doc);
foreach($xpath->query("//script") as $script) {
    $script->parentNode->removeChild($script);
}
$textContent = $doc->textContent; //inherited from DOMNode
echo $textContent;
?>

Advertencias:

content-from-a-web-page, line: 255 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 255 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 273 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 273 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 412 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 412 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 551 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): htmlParseEntityRef: expecting ';' in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 551 in /opt/lampp/htdocs/FB/ec2/test.php on line 13

Warning: DOMDocument::loadHTMLFile(): ID display-name already defined in http://stackoverflow.com/questions/12097352/how-can-i-parse-dynamic-content-from-a-web-page, line: 731 in /opt/lampp/htdocs/FB/ec2/test.php on line 13