How do I find why a xsltprocessor->transformToDoc failed?

[tcarnes]

I have about 8,000 xml files that I need to transform to html for display in a browser. The transformToDoc function is returning a "false" for about 1,000 of them and I need to find out why.

 

Is there a way to find out what the error was, why the transformation failed?

 

My code is:

$xsl = new DOMDocument();
$xsl->load('http://www.fda.gov/oc/datacouncil/stylesheets/spl/spl.xsl');
$proc = new XSLTProcessor();
$proc->importStylesheet($xsl);
$xml = new DOMDocument();
$xml->load($xmlFile);
$domTranObj = $proc->transformToDoc($xml);
if ($domTranObj === false)
{
    $isGood = 0;
    $error = 'XML Transformation Failed';
    // How do I find out why the transformToDoc failed?
    $numbad++;
}

Would someone help point me in the right direction? How do I find out why the transformToDo failed?

Terry