Hi Rich,
A corrupted installer means that something went wrong with the download. Unfortunately it's something that happens sometimes when you download things from the internet - not just with Sam & Max, and it's nothing we have any control over. (There's nothing wrong with the file we have up on our site.) You need to delete the installer and download it again. Here's a link:
http://www.telltalegames.com/download/cultureshock
If you want your money back instead, that's fine. Send an email to
support@telltalegames.com with your order number and we'll process a refund for you.
Also see my post
here. If you don't have an order number because of the crash, the email address you used or your first/last name will allow us to find your order.