Ok
When you register the software you need the CD key - that's the long set of characters in 4 digits.
That lets you run the software.
Th reach the download station (either the website of via the Content Manager), you need to be registered with Auran - as a username & password. (and you write that you have).
OK, now go into Content manager, and use the File -Options menu. There's a space here to enter your username & password. Once you have done that, the CM2 should be able to link your username with the serial number and allow you access to the download station.
I've no idea where you found the information on registering, but you have Trainz 2009 - not Trainz 1.0 (a much older program - with totally different procedures). You should have a manual on your disc (ok. 2009 ships with the 2006 manual, but most of it is the same).
Please be patient - your postings happened overnight (well they did here in the UK)
Colin