Cat Lady isn't really an antiquated game, released in December 2012. So, a few years old game.

Anyway, XP is listed as a supported OS so as long as rest of your PC meets the system requirements, contact GOG support for help (or a refund, if they can't get it to work), in case there is a reason you don't want to run the game on your newer PCs.

About using an old (XP) PC for GOG games, you have to be picky. I am also installing some GOG games on my ancient XP desktop machine (it has only 1GB RAM, a single-core AMD CPU etc.), but you have to know what is suitable for it.

For instance, DOSBox games are better left for newer/faster PCs because DOSBox in itself causes extra burden to the game/machine, and DOSBox games don't get any benefit whatsoever from being installed on an old XP PC. Also, games that use e.g. nGlide to emulate 3Dfx Voodoo graphics cards, I'd probably rather try to run on more modern PCs.

GOG games that I have installed on that old XP PC are mainly old Windows games from the late 90s or so, like Broken Sword (non-remastered version), Empire Earth, Dark Reign 1-2 etc.

you are correct: cat lady doesn't exactly qualify as 'old'. i chose it as a test because of the sale price and the relatively small download. my main goal is to use the xp machine for late 90s games that i used to play (using the retail CDs) back in the day when i spent a lot of time on the road & staying in motels. perhaps i should try a different,'actually 'old' one.

Is the XP machine a laptop (ie. did you use it back then when on the road)?

Yeah, I have a couple of old XP machines for the same purpose, they even have Windows 98SE installed on the side, just in case if some really old retail game has issues even in XP. One is a very old laptop (still working!) and another is the desktop.

I think I played e.g. the original Heavy Gear (retail CD version) on the Win98SE on that old laptop, the game had some issues both in XP and Windows 7.

Please, try installing the AGS Editor: [url=someone]https://www.adventuregamestudio.co.uk/forums/index.php?topic=49727.msg636497001#msg636497001[/url] solved the issue in this way.

EDIT:
I was thinking about a possible cause: your antivirus might have somehow quarantined the DLL file thus preventing the game to load the necessary library.

no, it is an off-lease desktop that i 'refurbished'. added ram, reloaded the OS, upgraded audio, etc.

Outdated java version . ( latest is Version 8 Update 121 )

i thought of that but since it is an old game i figured it would be looking for an older version of java, so i left it as is. for that matter, it may even be looking for an older version.