I purchased the CD version of the game at a retail store. I had run into the same problem a few others have had recently with the first episode in that when Gromit goes to town, the game freezes when you try to do anything. I used the method mentioned (removing the .dlg file though I stored it in a temp folder rather than deleting it) that helped to make that part passable, but now I'm up to the final part where Gromit is driving the truck. Nothing is showing up as something I can interact with which is causing me to be unable to complete the game. I can access my inventory but that's about it. While there were minor bugs in some of the other episodes, this episode seems to be the only one that has had bugs that made it unplayable.