No stuttering here
Apart from some issues with the downloading of TWW, i don't have stuttering problems with the videos - played nicely with no need of a cracked file.
I'm on a Windows 7 Home Prem 64-bit with 4GB, Nvidia GTX460 SLI, Soundblaster X-fi.
Try checking that the TWW2.EXE installer has the correct checksum after downloading. The correct checksum is in another thread related to 'NSIS error'.
On the other hand, i have problems with Puzzle Agent not being able to display the logs properly on the snowboard puzzle.