Trying this out, and I've spent the past day trying to figure out how to save my work. I followed everything possible (spent a good 3 hours looking to see what I'm doing wrong), but I always end up with the same problem. I attempt to save to web, and it always says username or password missing. I have filled out a username, and I have filled out a password, and it still complains about the same thing.
I fill in the tiddlyspot password in the WelcomeToTiddlyspot, What Now? section, and save this password on this computer is checked. When I click Save to Web, it tells me username or password is missing. I go to options, and fill in tiddlyspot password and username for signing edits, and even after that, it still says missing username or password.
So it appears all my work is lost. I've done this now 3 times, starting from scratch, ending up the same way. There is no documentation that tells you what username or password it is looking for. This is my last ditch effort. If I can't get this to work, I'm just walking away from this.