Adobe's activation software has a flaw that affects some computers with RAID drives.
(RAID drives are multiple drives in computers that act as one drive, with data being distributed over the drives as a form of real-time backup.)
The activation code thinks that the software -- Acrobat, InDesign, PhotoShop, and so on -- is being installed on more than one computer.
Initially, Adobe customer support told affected customers that they needed to buy additional licenses! Since then, Adobe has realized the problem is at their end, and is trying to fix it.
Don Fluckinger covers the details at "RAID Problem Exposes Adobe's Achilles' Heel".