I have been having the same problem. Using 1.10.51 on Windows Vista 32bit.
I'm using PS3 Media Server to stream my recorded Tivo shows to the PS3 (They are MPEG2 with AC3)
The shows play perfect for approximatley 15-20 mins but then the audio cuts out. If it 'Stop' and 'Resume' the movie the audio comes back and works perfectly.
Also, btw, PS3 media server is by the the best PS3 network streaming host that I have found and the only one that actually can handle fast forward/rewind of DVD .mpeg files.