I was able to install it without issue into my Win7 virtual machine (64-bit). I don't recall having any trouble with it. (Was a couple of months ago.)
Maybe try downloading from the net instead? I can't get the downloads tab on the product page on korad's site to work, but various vendors (e.g. SRA soldering) have the software hosted on their sites. And there's also a third party control program. The Web page is in German, but the software is in English. (Sorry I don't have the URLs handy, i'm posting from my ipad while googling on the computer.)