I have noticed two problems with a few of my DVDs of late and I was wondering if anyone here has experienced them (Note: I was trying to get answers over at a DVD forum, but no one there seems to make any sense)

Problem 1 (vibrations):
In my Denon 2900, a couple of DVDs (e.g. Crouching Tiger..) seem to cause an internal vibration in the player. And, I've tried this on a couple of 2900s as well as the 2200 with the same effect. It didn't happen on a couple of Sony's that the dealer had or the Denon 5800. Basically, when the DVD is playing, there is a vibration of varying severity. And, sometimes it only occurs when the disk starts-up. Othertimes, the vibration will continue throughout the movie. I'm assuming it is a 'very slightly' unbalanced DVD disk and that maybe only some players are prone to these vibrations. So has anyone else noticed something like this?

Problem 2 (LOTR TT glitch):
Has anyone here experienced the 'glitch' in ch 51 of LOTR TT? It happens after the battle when Galdolf et al., ride to the top of the hill and talk about "Saron's (sp?) wrath". Apparently, it manifests itself differently on different players. On some, it skips ahead a few seconds, on others it skips back to a previous chapter. On my Denon, it just pauses for a second or two. In addition, it doesn't even happen all the time on my player? Just curious if anyone here knows about this on this disk or any other DVD.