I am randomly guessing that "register" means "list" and the problem is that Shareaza does not come with a list of valid DC++ servers on install. But I know nothing about DC++ so...
eventually he could mean, there seems to be a lot of DC++ hubs requiring some kind of authentication (closed user groups?) which Raza shouldn't connect to. I faced this issue some weeks ago - got a connection, got kicked etc, while the chat window permanently flashed - had a hard time to get this hub off the list. Unfortunately I have no idea how to identify these.