Running Windows XP, especially on an internet-connected computer, is less than ideal, as you probably already know. Is there any kind of special applications you're using? If not, is Linux an option?
As for the ACSM files, if both Reader for PC and ADE refuse to work, there's probably not much you can do in terms of "official" support.
In the ACSM plugin thread I've also responded and attached a version of the plugin that should have the standalone scripts fixed (for the Raspberry Pi error you posted), so give these another try and see if that works now.
As for running them on Windows, you'd need to post the error messages you're getting so I or someone else can look into why that happens - I don't really have an XP machine on hand anymore to test this myself.
The latest version that runs on XP seems to be 1.48 - I can't even run that version anymore on a modern system and 2.0.0 changed lots of UI stuff around, so I don't think I'll spend the time making the Calibre plugin work with XP. The standalone version, though, should work with the bug now fixed.
EDIT: Also, for your testing, take a look at
https://www.adobe.com/solutions/eboo...k-library.html
That page lets you download a bunch of ACSM files for free that you'll be able to re-download over and over again, so you can test as many systems or applications as you want without eventually running into errors because a file is linked to another account, and then potentially losing a book you've bought.