5) Went into FS, and under Addon manager>Dreamteam>Honolulu, I clicked the 'register Serial' button and entered the correct serial number.
Since you HAVE the Addon Manager running, your problem doesn't have anything to do with it.
You don't have an activation problem, you don't have a registration problem, and you don't have an antivirus problem. If you had ANY of these problems, you would get either an error on activation OR, you wouldn't see the Addon Manager menu in the first place, which is the most common cause, when the antivirus is interfering.
If you see it, it means the software is running fine so, there's no need to do anything to "fix it", because it's working already.
All of the above happened with no errors except that I had to manually add the scenery to the FS scenery library (had to do that with KJFK also).
This, instead, IT'S NOT NORMAL.
Which just confirms that, your problem doesn't have anything to do with activation but, instead, there's something that doesn't work on your FS9 install or your Windows install, that prevents the Scenery Library to be updated automatically by the installer, which simply shouldn't happen.
Are you running FS9 under Vista or Windows 7 ? In this case, you might try running it as Administrator.