I'm attempting to retrieve the "shares" graph data for a number of pages in JSON format. I suspect that the errors I am encountering stem from the fact that some of the URLs have commas in them, and are being parsed as an attempt to pass multiple ids.

Returns graph data.  

<https://graph.facebook.com/?ids=http://celebritybabies.people.com/2012/08/23/backstreet-boys-howie-dorough-expecting-second-son/>

Returns error 2500 "Cannot specify an empty identifier"  

<https://graph.facebook.com/?ids=http://www.people.com/people/article/0,,20624518,00.html>

Encode the commas, still returns 2500  

<https://graph.facebook.com/?ids=http://www.people.com.people.article/0%2C%2C20624518%2C00.html>