i follow this wiki https://wiki.archlinux.org/index.php/Moonlight
1.Installing extensions from outside the Chrome Web Store is a hidden option in newer versions of Chrome.Download the Moonlight package for Chrome.
2.Make sure no page is currently opened inside Chrome that is trying to load Silverlight/Moonlight.
3.Go to the extensions page.
4.Enable 'Developer mode' (top right).
5.Now drag and drop the extension file you downloaded in step 1 to the extensions page.
6.You can now turn off developer mode if you wish.
at step 5 i get this error " could not load extension form '/home/sean/Downloads/google-chrome-extenison-moonlight'. manifest files is missing or unreadable."