I answered a question on SO a while back where I initially suggested using XML::DOM. After mirod suggested that I use XML::LibXML instead, I implemented it. And to be honest, it
I found that I have to add a repository, like the uwinnipeg repo http://theoryx5.uwinnipeg.ca/ppms/, when I am trying to install XML-LibXML on windows. Might be your problem too.
Use http://kobesearch.cpan.org/ to find repositories that have your desired ppms.
Also see my post on a different thread regarding how I was able to install XML-LibXML with ActivePerl 5.8.8.
In short, you can find the appropriate package in the corresponding uwinnipeg repository. NOTE see http://theoryx5.uwinnipeg.ca/ppms/ for the correct repository version to use, and XML-LibXML-Common MUST be installed first. Also, make sure you have the prerequisite DLLs installed before installing XML-LibXML via PPM.