BTW, I tried to reproduce the problem with the file on the local drive, and I could every time. I really think you're on the right track with VideoClock, at least on my system.
OT:
I listened to the sample loud on headphones so nothing would be able to hide from me. Gravedigger is one of my favorite Dave Matthews songs. It sounds great!
Yes, this is a great song, and the BluRay is amazing all around. I use this track to demo my 15 speaker (11.2) home theatre, and it sounds jaw-droppingly good upmixed with DTS NeoX. In my other 11.1 system that only plays 9.1 at any time, the combination of JRSS upmixing to 7.1 with (medium enveloping) and then further Audessey DSX wide speaker upmixing also just wraps the listener in audio bliss. 2 channel sounds good too, but I love being surrounded. Finally, bass transducers make it feel like you're on stage with them!