how to use themes?

Jan 4, 2013
Hello I have just downloaded the newest miui 2.12.28 for my galaxy nexus.
I tried to import a theme from the SD card but the theme chooser told me that its not an official theme and that I should download some similar from the marketplace...

So I tried.. but when I click on 'download' nothing happens. I tried many themes and its always the same..
Any solution for how I can download themes now or install those from SD card not downloaded the official way?
PS: I don't know if it maters but I am using the language pack (German)
Thanks in advance.