Have you upgraded your Wordpress to Version 2.6.3?
Basically, Techie Buzz article has given some basic steps to upgrade your Wordpress to the latest version. Do follow it step by step. (Warning: Applies IF and ONLY IF you are already running WP 2.6.2)
If your Wordpress version is not of 2.6.2, please perform a full upgrade.
Or if you are using the automatic plugin, don’t sweat it.