I explained myself in the wrong way. When I said that your credits are in Preferences.dat I want to said that in Preferences.dat is the userhash, which identify each user on ed2k network, so with this userhash other machines should recognize you and keep your credits, isn't it?
By the way, Should I need to copy any other file as well as the four I said before to keep my eMule credits?
Thx