They were obviously invalid clicks. If you asked your friends to click on them, what did you expect , do it the right way...
It can mean whatever google wants it to mean. Just follow the tos and let the traffic flow naturally.
Today I have yet to get 1 click. it's been really slow this month and last. It's tough but try not too look at adsense as a guaranteed income, instead just think of it has some extra pocket change lol
I'm glad Google works for you then. More glad that Google can detect the quality of your site from among the (shall we say?) the others...