Your license is indeed valid. If you still have a copy of the license it said ALL future versions of Winamp.
People here claim Winamp today is not the same Winamp as it was back then. But fact remains; Winamp back then was an MP3-player and todays it's an (drumroll) ... MP3-player.
There would be a difference if Winamp today would be the brand of a vaccuum cleaner or operating system, but it's not. It's basically an MP3-player and ff it looks like a duck, walks like a duck, it's probably a...
NullSoft claim all those licenses went void and null when AOL acquired the whole company but that's not the truth. There's nothing that indicates that NullSoft tried to hide the licensing model away from AOL. So, AOL must have had knowledge about it when acquiring Winamp.
This means they take responsibility for fullfilling all businesses, products and promises former Nullsoft has made.
As an example ABB, Ltd. d/b/a Combustion Engineering, the world's largest manufacturer of power transformers, was sued numerous times on products liability and tort theories for the injuries and damages that they claimed that they sustained as a result of exposure to asbestos used by Combustion Engineering in boilers that it designed, manufactured and sold. These products were all manufactured before ABB acquired Combustion Engineering however ABB, Ltd. had to pay more than $900 million in judgement and settlements in beginning in the 1990s and sought bankruptcy protection when its insurance was exhausted.
Same goes here. When buying a company, you don't just buy parts of your coosing, you buy the whole company, unless negotiated.
So, WinAMP is still an MP3-player, not a vaccuum cleaner, therefore I'd say your license is definately still valid.
Althogh you might have to fight it in court.
As for me, i download the version I want to use off the file sharing networks, confident that I have a valid license, no matter what AOL claims.