I am also seeing exactly the same ragdoll bug as shown in the Youtube video.
I don't know of any workarounds.
My setup:
PC Windows 7 (fully updated)
ATI Radeon 4870 (most recent drivers, (not beta))
Intel i7 920
Asus motherboard, P6T Deluxe ver. 1.0 (fully updated bios)
I only just started the game, so I may un-install and re-install. I'll let you know if that helps at all. I'm a little worried that even if I un-install, that some config files may not be erased.
P.S.: Update 03/10/2013
I did a complete uninstall and then re-install. Seems to have fixed the problem. VSync is on.