I use Terrapin, but with Freenetname, not ntl. I do have a problem remembering how to input all the info it asks for, but if I get it wrong I get the messages about correct authority, but nothing about dropped connection -- in fact I always have to manually disconnect because Terrapin never drops the connection even when I want it to at the end of an upload.
I'm suggesting that maybe there's another fault than just incorrect user name. But, have you tried the full "http:\\ www. user. name ..." (without the spaces)?