My activation was successful, but when it closed and I had to relaunch, it said that my trial period was over. I proceeded to activate my software again by phone, hoping that before it had been some sort of internet problem. I tried to launch it, but it brought up a screen saying that my "Trial Period" had ended, and that I needed to activate my software. Macromedia Flash MX 2004 included new features such as programming language ActionScript 2. It said that the activation was successful, so I pressed continue, and the activation screen closed, but Flash did not launch. Developers can build websites and applications with Dreamweaver, create interactive content with Flash, generate web graphics with Fireworks, and incorporate vector graphics with FreeHand.
I just got around to installing it today, and when I was prompted to do so, I entered the valid serial number that came in the box. Macromedia Studio MX 2004 integrates the leading professional tools for developing the full range of web sites and internet applications.
Anyway, they went ahead and got me an unopened version of Macromedia Flash MX 2004, which, of course, no longer has any sort of customer support. Unfortunately, I did not specify which version of Flash I wanted, so they immediately got the cheapest version they could find (and I don't really blame them). I'm not sure what to advise because Adobe Customer Care won't support MX 2004 beyond pointing to the link in your reply. The OP is saying that not even that serial number is working.
For my birthday this year, when my parents asked me what I wanted, I told them all I wanted was Flash. The serial number that was posted by the OP is the published serial number in the legacy Macromedia link in your post.