The file you download from github is a zip file, unpack that. That'll give you another folder, inside that folder is the folders you actually need. Take the ones you use and put them in to the addons folder.
If you just take the "Master" folder and put that in to the addons folder, then it won't work.
Newest Carb version can be found in this post:
http://www.wowinterface.com/forums/s...249#post320249