It has come to the attention of the WordPress support team and developers that there is a tiny problem with WordPress 2.0 and trackbacks. They are investigating the situation as it isn’t consistent, though it is consistently reported. There is a new patch that seems to fix the issue, but the investigation continues.
According to Playpen’s WordPress 2.0 Broken Permalinks and 404 Error post:
UPDATE: Another part to this story seems to be that it was to do with the timestamp, rather than anything else. The trackback URL on Lorelle’s site from me had the timestamp of 01/02 (2nd of January for us Europeans) but my post timestamp was 01/01. No idea why that should be or how it happened. So I’m not sure if Ryan’s patch made any difference at all, but I’ll leave it in anyway. I restamped the time to be 02/02 and now everything should work (unless you linked to the old one, heh).
Here are more links to help you understand what is going on and find the solution.
- WordPress Support Forum – WordPress 2.0 Messed Up My Permalinks
- WordPress 2.0 404 Problem on Permalinks