I was running WordPress 2.8.
Automatic upgraded failed.
So I uploaded the files manually and, at first sight, it worked.
But now, everytime I create a new post, I have an error message when I save it as a draft or I publish it directly, even if it is actually saved and I can access it when I go to the POST section of from my DASHBOARD.
The error message is : "Your attempt to edit this post: “little test” has failed."
Any idea ?