Sounds like a keygen crack issue - which you appear to have already discovered in the main thread. Not sure what impulse does about this, but it's probably the same thing as steam. Of course the problem is that when you're registering a key obtained from a third party (yes, the publisher counts as such in this case) it's difficult to determine who the correct owner actually is without a lot of time and effort. Otherwise it turns into "he says, she says".
Though it's unlikely someone with a cd cracked copy wouldn't just run it again when it didn't work the first time, it is possible they might call in and claim to be the legitimate owner, so you have to verify. As I said, this takes a lot of time and money, and as a result is something valve/stardock (ie, steam and impulse) as well as publishers in general will avoid like the plague.