I tried running Deskscapes on my XP Home SP3 32 bit system with low end nVidia card (GeForce 5200) and it just couldn't hack it. The system has a P4 cpu and so it may not have had enough processing power to handle it.
In your siituation I would go back and take a look at would you really use Deskscape. They are nice but I gave it up because I came to realize that I wouldn't use the function, as nice as they are. In other words I have a desktop set up to be usable, I have docks and widgets that I like, I was not going to move or lose them so I could look at an animated wallpaper.
I have since gotten a new computer with much better specs and Vista Home Preimum, and I still don't use Deskscapes. I don't shut this one off, put it into sleep mode so I'm not using boot or logon skins either. I do use a screen saver.
So reevalute if you really would use Deskscape, if the answer is yes than you might be in for some upgrading of your current system, might be better to look at a new computer if the money becomes available.
Now don't get me wrong, I love the programs and software that Stadock puts out. It's just that I find that you make choices as to what you run. If I were to give advise I would not get the 'cheapest' nor the most 'expensive' card when upgrading, get the best one you can afford within your budget.