getMemberGroups and HTTP 404 Error

I was using getMemberGroups function to obtain all groups for given user, as it had been described in http://blogs.msdn.com/b/aadgraphteam/archive/2013/05/15/announcing-some-new-capabilities-in-azure-active-directory-graph-service.aspx.

For a last couple of day i become always HTTP 404 Not Found Error. Has been this function deleted other api-version parameter has been changed ?

Thanks for an answer.