After about 40 hours in, I began suffering some horrible freezing issues (detailed http://www.gamesas.com/index.php?/topic/1272910-cant-use-my-weapon-and-magic-they-freeze-up/page__gopid__19271070#entry19271070), so I thought I'd try starting a new game and seeing how it performed... my fellow prisoners don't talk to me, and when we get to Helgen, nothing happens, we all just sit there staring at each other. Anybody else had this?

Sadly, it's to the point where Skyrim is completely unplayable for me. Such a bummer, since it's easily one of the greatest games I've ever played. Help, Bethesda!

The exact same thing happened to me! Except its been like this since I put the disc in, I made a post about it here: http://www.gamesas.com/index.php?/topic/1262691-intro-glitch/

Somthing like this also happend to me, but the game started with me and the rest of the "gang" not even in the cart, we were just standing around but the sounds made seem that we were riding in a cart... All I did was restart and that fixed the glitch...

Have you tried installing the game? If so did it say disc unreadable at the same point everytime despite it being a new disc? Mine did, even when i tried clearing the system cache

This happened to me the first time I put it in to play it.
It worked after I took it out and put it back in though.

Tried that lots of times, quite a few fixes but none of them are working for me

When I first got home with the game I installed it to my 360 HDD in spite of the known texture issue. I started the game after the install was complete. Well to my surprise all of the characters, including myself, were standing completely still outside the prisoner wagons and the wagon and horse hoof audio was playing as though we were moving.

I quit to dashboard and rebooted and the game started fine.

It was a scary moment though.

Had a similar problem about 6 hours in when everyone stopped talking and the Quest progression ceased.
I tried starting a new game and while in the wagon no-one talks and I just get stared at by the guy that's suppose to greet you when the wagon does get to the town nothing happens.