I replied to this post, indicated where the option was, and then immediately deleted my reply. I'm having trouble understanding the problem. You're unable to find the option to configure last.fm (Tools > Option, enter "last.fm" in search area), or are having trouble locating where to go to play last.fm (Audio > Connected Media > Last.fm), or you've done both of these and still are having trouble (if so, please provide more detail...).