Hi, We recently purchased 2 copies of Acrobat Professional, it came with a single key. I managed to install and license 1 PC with the code but when I try to license the second PC I get the following error, "This serial number is not valid for Adobe Acrobat. You can either use a valid serial number for Adobe Acrobat or use this serial number on the appropriate product." I used the same installer on both PCs so I'm very confused. Any suggestions? Thanks Paul ... View more