I had the same problem. Appearantly there is a problem with the Multicasting of the router when you connect your PS3 wireless. Try first having switching on / off multicast streaming (in advanced network settings) if it does not help, connect once directly wired to your router. If you want to use wirelessly, I'm willing to send you my screenshots in which I got it worked so that you can try the same at your side.
Let me know !
Good luck !