don't do it through windowblinds by hitting the "download from Wincustomize.com" button.
I did exactly this and it worked for me. With no problems...
I will say the Error the OP is receiving is a new one to me. Would probably be a good Idea to Email Support@Stardock.com stating exactly what is happening, as well as your system info from Windowblinds System info tab.
If when you click on the download button and the download comes in a .zip or .rar try extracting the files out into a separate folder. When trying to install files that are compressed they may not be read properly.
I don’t know how to change the file extension
To change the file extension you need to make sure that can see the extension type. In order to do this you need open an explorer windows (ie: my computer, my documents) and at the top where it says file, edit, view etc. Click on tools then go to folder options. When the window opens up, click on the “view” tab and in the window look for “hide extensions for known file types” make sure this box is unchecked. Then you should be able to see the file extension at the end of each file. The file extension is generally the three letters after the period in the file. Just like .com at the end of a web address. So you should be able to see .wba or.zip or .rar at the end.
I have experienced this before. I alleviated the problem by uninstalling Windowblinds and reinstalled and I also do install through Windowblinds. Windowblinds will recognize the download and automatically and open and install the skin. I also have seen the .uis error when dealing with a corrupt or damaged .wba file
To uninstall a program I use a program called Revo Uninstaller,
Revo Uninstaller is a freeware innovative uninstall utility much faster than Windows Add/Remove applet. With its advanced and fast algorithm, Revo Uninstaller scans before and after you uninstall an application. After the program's regular uninstaller runs, you can remove additional unnecessary files, folders and registry keys that are usually left over on your computer. Even if you have a broken installation, Revo Uninstaller scans for an application's data on your hard disk drives and in the Windows registry and shows all found files, folders and registry items so you can delete them.
This little puppy is awesome. Especially when I am going to do a reinstall because it wipes out any instant of the program being there before.