Did you ever get this working? I just got a Sony BDP-S570 blue-ray player with wireless, and it recognized my media library on my Windows7 64 bit machine immediately. All i ever did on my PC was in control panel, network and sharing center, choose homegroup and sharing options, choose homegroup and sharing options, and check the box to stream my pictures, music .....
I also went into Choose Media Streaming Options and did Allow All.
At one point my BD player would not list all the movies on my PC. I changed the library name (in the Advanced Media Streaming Options screen), rebooted the PC, waited 5 minutes and i was streaming movies again.
My BD player has firmware version M04.R.735. Hope this helps.