I really think you need to consult a copyright lawyer over this - the guy could be fishing... send out 100 emails to see if anyone offers to settle out of court.
He now has you on the line wiggling... perhaps another question might be worth putting to the forum...
Anyone know any copyright lawyers that can offer some quick free advice... Yeah I know... lawyers and 'free' don't usually appear in the same sentence, but then again this is a rather special forum. The KPA user network spreads far and wide...
I'll continue to follow this thread - rooting for you...