I tried that and it didn't solve my problem, so I ruled out the cable. I also ruled out the receiver because the exact same scenes don't have audio drop-outs when played on my XBox.
I'm glad I noticed this thread. I have the Toshiba 4800 DVD player, and have noticed drops on all of the LOR Extended Versions. I was really getting annoyed with it this past weekend watching ROTK. For that one, I know I was using the DTS-ES track; for the other LOTR DVDs I was probably watching the DTS track as well although I'm less sure. I was planning to ask the same thing -- reciever? player? interconnect?, but decided to search first.
I suspect my 4100 may be similar enough to your 5700, that they may both have the same problem with the same track. If you post the times of your consistent drops, I can go check if I have the same issue. Mine isn't really that old, so I don't think it's wearing out -- I suspect this player just has issues with these tracks.
I have a Denon 3802 receiver, and a very cheap digital coaxial cable. My first guess was that the receiver was getting too hot due the the almost continuous background music, but I checked the receiver and it was pretty cool. A DVD player issue does seem to be a good explanation.
I'm pretty sure it's the player. I returned 3 newer Toshiba players(still looking for a good inexpensive progressive player) and all of them had audio dropout issues The 6915 changer was the worse. In fact not too long after I called Toshiba about that and registered my info, I got a letter from a lawyer about a class action suit against Toshiba.
Well, that kind of stinks, because other than these occasional drop outs, it's been a champ. Guess it gives me a good excuse to snag one of the upscaling DVD players while you can still get one that does it over component (albeit with a hack).