Windows 7 themepack fixed!
Apparently I did a little mistake saving the themes. Thanks to Zia for bringing this to my attention!
You can now download 9 high-quality working themepacks here. I also included a readme.txt but all you have to do is to double-click them.
Want to create your own themepack now? Open this page and scroll down to the bottom, there will be a short guide how to save your themes properly.