Adam Michael, I don't use SkinStudio 6, but WB6 is working just fine with my windows XP Home system. Yes these are beta versions and most things will be cleared up when the actual versions are released. I don't think you need to purchse Vista, unless you want to.
Some older WB's may not be able to take advantage of all the new features. The most popular ones will usually be upadted by the skinners to work with WB6.
So, you actually called the support folks, and they returned your call. WOW!