To be truthful they are just scum bags, but really not doing anything wrong. They are by the looks of the debug line, using an older version of PhpBB so I would not worry about it...
You don't think they're doing anything wrong. And you wouldn't worry about it. Well, that's a relief.
On the other hand, it doesn't make any difference what you think. I know that sounds mean, but are you one of the wonderful people who spent thousands of hours of their free time creating phpBB2 for us so that we could use it for free? It doesn't sound like you are. I know I'm not.
If you're not involved with the development of phpBB2, then you would probably be wise to let those who are respond to messages about copyright issues.