I upgraded to latest version of WP and the problem was fixed.
I’ve always thought that upgrading from WP 1.5 would be a pain but it turned out to be quite easy – just 45 minutes (and I made 3 different backups to make sure that I could restore the old site)
But I think that the problem of this thread is quite weird. I believe that thousands of WP-users have had this problem (I actually met a guy on the street the other day with the same problem). Someone must be able to explain what’s wrong with old versions of WP.
(How do I mark this thread “solved” ?