Till now, I cannot delete comments from my PC, XP, firewall turned off, cookies and cache cleaned up. But now, it turns out that I cannot add links to the blog either, I get exactly the same error message as for the comments, i.e.
Sorry, you need to enable sending referrers, for this feature to work.
Now, I suppose I can go to my iBook, and do the job from there. But that means that if I want to blog, I'll have to carry my iBook everywhere.
This is a big drawback for me. Thanks for your help.