WindowsUpdate error 0x8DDD0004 on windows xp

Hello
I get this error when trying the windows update.
I never used windows update before, since that pc has never been
connected to the internet, until now.
I have searched the web for answers; first I found some advice on the
official microsoft website (knowledge base, I think...), that was about
registering some dlls. No good.
Then I found lots of messages on this NG, but I still can't get through.
For example I looked at this:
http://www.tiny.cc/XD2xf
by the way, when I restarted the cryptsvc, I got a message that it was
already running, even though I am sure I stopped it before
re-registering those dlls.

So, what I have done so far is (unsorted):
1) check on firewall / popup block
2) clear cache and cookies
3) clear software distribution directory
4) re-register some dlls
5) make sure that I use an administrator account
6) check over "update root certificates"
7) check through WUWebControl Class in Internet Explorer

Still, I get no "install this activex" messages; I just get that error.
Nothing more.

Is there anything I should try that I haven't already?

Thanks.

p.s.: it is windows xp professional, sp2