I had problems a few weeks ago (when a lot of other people were having problems, and Helpdesk admitted that something was wrong). Then I was still having problems when other people seemed to be getting in OK... so in the end I requested a new PIN.

Contrary to what it still says on the web site, the PIN didn't take weeks to arrive - it didn't even take days to arrive. It arrived, by e-mail, within a couple of minutes. And the new PIN worked.

So - you may want to try that!