Very strange indeed. Did you try replacing your wp-comments-post.php file?
I would think that replacing that file should work. 🙂 I just use the WP out of the releases, I don’t use nightly builds. Could be something in the build? Why not download the latest version from Source Forge and replace that file to see if it works. 🙂
I would suggest at LEAST using the 1.0.1 Release Candidate as it fixes a bunch of 1.0 bugs. However, I can’t for the life of me figure out why your comments do what they do. Have you tried turning off comment moderation?
It is a redirection issue. Changing your siteurl from http://www.frog-net.co.uk to frog-net.tufmedia.net will fix it.
I notice that your blog is hosted at http://frog-net.tufmedia.net/ while your siteurl points to http://www.frog-net.co.uk which is then reflected to frog-net.tufmedia.net via a DNS redirection. DNS redirection (which is effectively an HTML redirection of some sort) munges http POST messages and your comment post gets lost in that transfer. The reason that posts work fine is because they dont source your siteurl but maintain a relative path on your server.
Hope this helps.
Peace
Cheers LaughingLizard, that worked a treat!
Thanks to everyone for taking the time to help me 🙂