I think that FQL became deceprated by the beginning of August. I've solved this problem using graph API and stating the fields argument
fields=likes.limit(0).summary(true),comments.limit(0).summary(true)
the fields likes and comments would give you a list of people who liked or commented on it, the .limit(0) means that you don't need any exact names mentioned and .summary(true) gives you more detailed info on it - the number of likes/comments.
I hope this explanation helps, you can find more info here https://developers.facebook.com/tools/explorer
