You can only trace someones IP address is if its a public address. Idividuals do not have them, organizations do. Everyone else is hidden behind Firewalls that translate your internal address to that of a public 1. BT, Virgin, BBC.. they all have public address and issue some to large organizations which take a lot of server/traffic hits.
This is obvioulsy a scam but you wont ever find him, report it and thats about it. He'll be some big horrid Nigerian with AIDS no doubt sat in some sweaty fly ridden internet cafe in Lagos or somewhere..