Today, the Wordpress team just updated Wordpress 2.7 from Beta 1 to Beta 2. It seems that the Wordpress team had to update the Beta 1 version of Wordpress 2.7 becuase of some fixes to the coding and patches here and there. A list of the fixes can be found on the Wordpress 2.7 Beta 2 blog.

Not to mention a quick tip, "Beta 1 does have a bug in the automatic upgrade that breaks certain setups, so be prepared to download and install Beta 2 manually if you experience problems." - Wordpress 2.7 Beta 2 blog.