I have tried to download the demo for DDS:PB18 multiple times today. Every time I do, just as the download ends, I get the message "The publisher of DDSPB18Install couldn't be verified". When I select "Open", I get a window with the header "Open with", followed by a list of programs to choose from, none of which make any damn sense for doing this. By the way, I've never seen this behavior on a downloaded game before. Not even DDS:PB3.
How do I play a game that won't let me install it?