Stage 1 works perfectly, Stage 2 fails to seperate

UnderCoverPenguin writes: In the 3rd launch of Falcon 1 (http://spacex.com), the first stage, with the latest version of the Merlin engine, works perfectly. Unfortunately, the second stage failed to separate. (http://www.spacex.com/updates.php) Hopefully it was only a minor setback, despite the huge cost.