Indeed, only Adobe can help you. How did you come to have an Acrobat 9 upgrade but no earlier version? (People often buy new software with this problem and have to get a refund then buy the full version; but presumably you have been using this for years and now want to reinstall?)
The message does not say you are entitled to an upgrade, I suspect. If it is the message I am thinking of it wants you to prove you are entitled to an upgrade.