That's bizarre. It's supposed to allow you to transfer the registration since you've provided the original serial number and hardware password--sort of a form of proof that you have the hardware in your care. If the device is still within the software update contract (1yr from initial registration), that might have something to do with it.
There have been many reports of people having registration problems of varying kinds, some due to knock-off clones, some due to earlier registrations, some due to corrupt files, etc.
If you genuinely can't update the registration, you'll need to contact the support number and let them know. A documented response has been that Support will often be borderline belligerent about helping unless you renew the support contract. That's not necessarily true and I would hold them to honoring the transfer so you can legitimately try the product out under your, legal, ownership. Perhaps it would be helpful to publicly post your experiences with Support, here or in a new post(s).
-Jeff