Initially, when I first heard the news, I thought it was a no-brainer. The District Court definitely erred. The Appeal Court simply uphold the status quo. It did, but, as usual, is not that simple.
This Groklaw article cut through all the fuss to the heart of the matter. Slightly more details in this Groklaw article. The “enemies of open source” as PJ puts it, was trying to reduce the Artistic License, from a copyright license to simply contract terms. Legally there is a lot of difference, not only in monetary terms, but most importantly, burden of proof: It is much more difficult to wiggle out of copyright infringement. District Court thinks that because there are a lot of freedom granted by the Artistics license, it is in effect a contract dispute. Fortunately for open source, the Court of Appeals disagree. Their argument is what the other party had done is outside what the original author had permitted it to do and therefore, it is a copyright infringement problem, since copyright law give the authors the monopoly rights to control the particular activity the other party is said to had done.
However, I tell you what is scary. As Koman point out, the crucial point turns out to be the wording of the contract, in particular the two words “provided that”. That’s scary because layman like you and I would not had been careful in our words. Therefore, PJ is right, you need your lawyer to draft the license.