There is a pretty good article about using the MSXML parser at perl.com (MSXML, It's Not Just for VB Programmers Anymore). The article includes quite a few examples of error catching and an example of the DOMDocument->transformNodeToObject method.

Just out of curiosity, why are you using MSXML rather than one of the perl XML modules such as XML::XPath, XML::DOM or XML::Twig?
----
Coyote