Sorry that didn't work. Maybe someone else can suggest something.
The other causes of this type problem are somewhat more difficult to find, especially with Vista, and I'm afraid I have no other ideas except to suggest you search the forum - probably with Google so you can use specific key word combinations with your OS, etc.
There is a
remote possibility that it may be a problem with unzipping the downloaded file. This has been mentioned - but doesn't seem to be consistant between users. You might also try another download and unzipping with 7-zip. Probably a long shot - but if it should work, please post that result.