.. help. It looks like, one cannot initiate a new aircraft profile if the tail number is included in the database, even if it's deregistered. I tried to upload a brand new Boeing 737-924ER with the registration # N68452, this database thinks it is a deregistered Cessna! I submitted a bunch of corrections but it is a very clumsy (and frustrating) process.
You need a "New Aircraft Profile" link in the Member Home with a procedure to resolve conflicting entries.