Culture Shock does not activate properly on Vista. It's the only episode that has this problem and we will release a fixed version soon. Clicking "I've already purchased this" and entering your order number and password is a temporary solution. After doing this a few times the game will start saying you're out of activations. You're getting close to the end so you might be able to finish before that happens; if not, email us at email@example.com
and we can increase the activations so you can finish the game.
There's also a Vista-compatible version of the game that we can send you -- again, just write to firstname.lastname@example.org
and ask for it -- but due to the holiday weekend coming up we might not be able to get that to you until Tuesday.
Episodes 2-6 do not have this problem if you don't mind playing them out of order.