Hate to pile onto this, but I too can't download Episode II, and I just purchased The Walking Dead a few days ago. It always gets to 99.50% and then it just stops. After that the download seems to go haywire because it actually shutdowns my internet connection for everyone in the house.
I've tried like six times now. I've turned down the graphics, set the resolution low as it goes, ran the game in windowed mode, ran the game in full screen, deleted the temporary files in my application support folder. Never gets beyond 99.50%. And this is just for Episode II. Not looking forward to repeating this nonsense to get Episode III, let along Episode IV or V when they come out.
Looking at the dates of these other posts, it's ridiculous Telltale is still selling a Mac version of the Walking Dead while these issues still persist, let along refusing refunds. They should probably just take down the Mac version for the time being until they fix these problems. Or just offer us an alternative way to download the other episodes.
If there really is no way to get a refund or resolve this problem, I guess I'll just have to dispute the charge with PayPal, since I'm not getting the product I paid for. I would just like to find a solution. I really enjoyed the first episode, but this hassle has really soured me on buying anything else from Telltale.