Hello James,
I don't think you're doing anything wrong. I've just tried to log in as a new user to add content, and am experiencing the same problem as you. I don't have access to the technology behind the website, so am unfortunately unable to help. It was created a long time ago now, by Holy McGrail. I suggest you send a request to him via [email protected]
and failing that, perhaps to his company at [email protected]
Apologies,
TMA Ed.