I have heard that the PS3 has problems with some audio on blu ray such as TrueHD. Have you heard of that?
You cant bitstream but LPCM is just fine..
Setup info here http://www.engadgethd.com/2009/04/21/hd-101-how-to-use-dolby-truehd-and-dts-hd-with-your-ps3/