Retested it = OK......I don't understand WHAT and WHY you get as corrupted....
tested installation on my win 7 - 64, no problem....
Download OK, unRAR = OK, Installation OK, Working = OK
So, what ????? i don't know....
Below, the link to sequential screenshots of what i have done.....
Good luck.
https://imgur.com/a/MEIqBGR