Serial number not working?

My laptop died. I bought a new one, second hand but fairly recent. I bought a new drive for the newer computer, and cloned over everything from the original drive - which is fine. Everything works fine in the newer computer (MacBook Pro 2010) now. But of course, when I open some of the apps they want me to insert the original serial number. This has worked fine with my Final Cut Pro Studio and my Logic Audio. But when I try to open Aperture it asks for the serial number, which I'm taking from the Aperture app on the original drive, from the 'Licensed To window': and there it is, I can see my name, my company name, and the serial number. But when I insert it in the pop-window on the new computer it says the serial number is invalid.

I can't remember if I got Aperture as a hard copy, or downloaded from the Apple store. I'm 3,000 miles from my office where the box might be. The app was (and still is) working just fine on the original drive.

What might be happening here? And is there a way to check with Apple on that serial number? To confirm it perhaps. I'm sure if I look I can find the original sales receipt somewhere stored on this computer.

I think I purchased the first version as a hard copy, then upgraded it several times using the Apple Store downloads.

All ears,

Ben