We were having server problems today. The result, the Zurich for FS9 installer file was corrupted on the server, starting from 9:00 AM (Italy time) to 19:29 PM.
Just download it again, it should be fine now or, use this alternate link:
http://www.virtualisoftware.com/binaries/zurich9_setup.exeWe are undergoing a total server update in September, which should hopefully solve this problem.