Posted from my CrackBerry at wapforums.crackberry.com
It may say that it's available but I can almost guarantee that it will not work.
As mentioned, Themebuilder for OS 7 is not available yet.
It is probably a mistake by the developer in listing compatibility with the Torch 9810.
App World saying it's compatible and it actually being compatible are two very different things RIM doesn't check device compatibility. Nor do they give refunds...
There was a Beta Theme Builder released at one time that had OS7 device support, but it was pulled. I've been trolling trying to find which one it was and trying to download it, but I have not had any luck. I'm hoping we get something soon, I've got several ideas and want to get working on them as soon as I can. I'm still dreaming for a Mac version and hoping that is why they are delaying it...