The captcha was the question-based one, and I was "logged in" on my LJ account. It failed multiple times and gave me the same question each time. As anon, it still failed a couple of times, at least once with no reason that I could see, once may have been that I entered the answer (a number) numerically instead of writing the number out. I sent Dreamwidth an email and got the standard automated reply; still waiting to see if they respond usefully.

Trying the LJ OpenID again...