We purchased 2 licenses for Adobe Acrobat X Pro to allow us to digitally certify engineering plans in PDF form, and now this installation of Acrobat X Pro says the "serial number you used to activate the product has expired" and this "is your last opportunity to launch the product before it is automatically deactivated." It also says we "must provide a new serial number or start a trial on next launch."
Why? Why would we need to re-purchase serial numbers when we purchased the product already?