Very odd, haven't seen that happen before. The code for returning the version of MySQL you are running is not returning any value. This could be some sort of server configuration issue. That is a status message, not an error. You should be fine as you are running MySQL 5+.
Carl, here is the fix: http://codex.wordpress.org/Updating_WordPress
Here is the proof: http://screencast.com/t/MNaLRYWd
Carefully, I did a manual upgrade of WP. One note: There is no .maintenance file created in the root directory, as mentioned. All good now, thanks.