CS6 Design Web Premium: Mac to Windows?

So I have a perpetual liscence (for CS6 Design & Web Premium) that I bought back in 2013 for my Mac at the time. I would like to download this onto my current PC since I no longer use my old Mac. Adobe Support gave me the download links so I could install the software. After inputting my serial number, there is an error that pops up stating that the serial number is not valid.

Is there anything that can be done?