A quick look into the zip at XML-XPath shows that it only contains the code for SUN-Solaris builds of AS unfortunately. If you have subscribed to a support contract with AS, you can request that they make it available, and they may do so. Otherwise, I think your into the situation of having to A) search the web to see if anyone else has a Win32 binary version available or B) Prevailing upon someone else with the wherewithall to build a copy for you.

Update It would seem that assuming you have installed XML::Parser, that XMP::XPath doesn't have any other binary components, so you ought to be able to install it successfully using the CPAN module.

Failing that, with a little care, it is totally feasable to install it successfully manually directly from search.cpan.org. I know, I just did it! There are 21 files and 2 directories required to do it, but it took me less than 10 minutes saving each file directly from my browser. I don't claim that I have a fully tested install, but I did run install and run the stress.t test successfully.